









Book_ jB.5 



COF/RIGHT DEPOSIT. 


\ 










A KEY 


TO THE 

ELECTROCARDIOGRAM 


BY 

LOUIS FAUGERES BISHOP, M.A., M.D., Sc.D., F.A.C.P. 

ti ' ' 

PROFESSOR OF THE HEART AND CIRCULATORY DISEASES, FORDHAM UNIVERSITY ; SCHOOL OF 
MEDICINE, NEW YORK CITY ; CONSULTING CARDIOLOGIST TO THE LINCOLN HOSPITAL ; 
FELLOW OF THE NEW YORK ACADEMY OF MEDICINE ; MEMBER OF THE AMERICAN 
MEDICAL ASSOCIATION. OF THE MEDICAL VETERANS OF THE WORLD WAR. 

OF THE AMERICAN THERAPEUTIC SOCIETY, OF THE NEW YORK PATHO¬ 
LOGICAL SOCIETY, OF THE SOCIETY FOR THE PREVENTION AND RE¬ 
LIEF OF HEART DISEASE, AND OF THE ALUMNI ASSOCIATION, 

ST. LUKE’S hospital; AUTHOR OF “ARTERIOSCLEROSIS” 

“HEART DISEASE BLOOD PRESSURE AND THE 
NANHEIM TREATMENT,” AND “HEART 
TROUBLES. THEIR PREVENTION 
AND RELIEF.” 


ILLUSTRATED 


* > 

> -> > 
O ■> 


NEW YORK 

WILLIAM WOOD COMPANY 

MDCCCCXXIII 


PRINTED IN THE UNITED STATES OF AMERICA 



Copyright, 1923 

By WILLIAM WOOD & COMPANY 


Press of 

Hamilton Printing Company 
Albany, N. Y., U. S. A. 


APR 2 3 *23 

© Cl A 7 05051 


'***» l 


PREFACE 


The electrocardiogram lias raised the treatment of disorders 
of the heart from a speculative undertaking to one founded on 
a very definite plan of procedure. A great student of the heart 
is said to have remarked in a comparatively recent lecture that 
the invention of the stethoscope held back progress in cardiology 
fifty years. His meaning was, that undue reliance upon inter¬ 
pretation of abnormal sounds of the heart has given a false 
sense of knowledge which has resulted in many errors. 

Auscultation is, of course, valuable in the detection of regurgi¬ 
tation through incompetent valves and on some occasions in 
the detection of narowed valvular orifices. In the latter in¬ 
stance, however, the inference is as apt to he incorrect as cor¬ 
rect. So long as no other method was available, it was abso¬ 
lutely right for physicians to cultivate their powers of auscul¬ 
tation to the last degree, but now that new and much better 
methods have been discovered and perfected, they should be 
adopted promptly. 

I will try to impress the advantage of electrocardiography 
over ausculation by a homely comparison. 

The heart is shut up in the chest and is therefore not subject 
to inspection. In like manner a frog may be shut up in a 
box. Now suppose four wise men were seated around this 
box with the frog inside, and each, with his ear close to the 
box, was listening to the frog to see if he could determine 
which legs the frog was moving or what he was doing. 

One wise man might say: “I hear a scratching sound and 

1 believe the frog has moved his right front leg;” another 

might venture: “I heard a loud thud and I am sure the frog 

has kicked his left hind leg,” and the third man might assert 

that he heard a general scratching and pounding sound and 

believed the frog was moving all four legs. After retiring to 

an adjoining room for an hour or more to debate and discuss the 

matter of which legs the frog moved, the wise men would have 

• • • 
m 



IV 


PREFACE 


reached no definite conclusion as to just wliat the fiog had 
been doing in the box. 

Now suppose these same men returned to the room where 
the frog was shut up in the box and attached a piece of string 
to each of the frog’s legs, and, after labeling the strings as 
to which leg each was tied to, they hung the strings outside 
the box. They could now determine by watching the strings 
just exactly wliat the frog was doing with his limbs. 

Later on, assume they discovered that each time the frog, 
moved a limb the contraction of that muscle generated a cur¬ 
rent of electricity of a type peculiar to that particular limb. 
If a wire was attached to the frog and if the little electric 
currents which were generated when the limbs moved were 
collected, it would be possible, by studying these currents to 
find out which muscles the frog was using when he moved his 
limbs. If we substitute the human heart for the frog these 
things which have just been mentioned have actually been 
accomplished. Each muscle bundle of the heart as it contracts, 
generates its own particular electric current. These currents 
are collected by wires attached to the limbs of the person under 
examination, and the currents are sorted out and studied by 
passing them through a fine filament between the poles of a 
powerful magnet. The filament sways back and forth according 
to the quality of the current passing through it. The shadow of 
the string is photographed on a moving film, and when printed, 
an exact picture of the activity of the heart under examina¬ 
tion is obtained. 

This in simple terms is electrocardiography, a painfully 
long name for what is in reality, a very simple matter. It is 
hard to believe that so simple and wonderful a method of study¬ 
ing the heart action has been so long in reaching the whole 
medical profession and in being put to general practical use. 

It is a fact that many hundreds of people are relieved every 
year through the knowledge of their condition which is 
obtained by means of the electrocardiograph. It lias made 
many previously fatal disorders of the heart perfectly clear 
and daily enables a positive distinction to be made between 
serious and innocent heart troubles. 

This book is in part, an expansion of papers which were read 
at various times before groups of specialists and general practi- 


PREFACE 


V 


tioners. The possible usefulness of a book of this character, 
containing in simple form the rudiments of the subject and 
omitting all matters of controversy and rare cases, was sug¬ 
gested by the comments of a number of these men who were kind 
enough to tell me later that they dated their interest in 
Cardiology from the time of my paper. 

I think it was Huxley who said that he had frequently been 
accused of a lack of technical knowledge of his subject when 
he had attempted to present it in very simple terms. It is 
true, indeed, that a presentation in allegorical form puts one at 
the mercy of a certain class of critics who are educated beyond 
their intelligence, but this is more than counterbalanced by the 
approval of the average reader when supplying him with an 
easy grade, up which to climb the first steps to what must, of 
necessity be a very difficult subject. 

I would be ungrateful indeed if I did not express my ap- 
preciation of the help rendered me by my associates and by the 
publishers in preparing this little book. 

109 E. 61st St. 

New York. 


Louis F. Bishop 









CONTENTS 


CHAPTER I. 

Use of Graphic Methods and History of the Electro¬ 
cardiograph . 1 

CHAPTER II. 

The Electric Autograph of the Heart of a Healthy 
Person. 12 

CHAPTER III. 

The Time Element in the Electrocardiogram. 24 

CHAPTER IV. 

Sinus Arrhythmia. 27 

CHAPTER V. 

Heart Block 

Instances in which the Ventricle Acts Abnormally 
AFTER THE AURICLE. 32 

CHAPTER VI. 

Complete Heart Block 

Instances in which the Auricle and Ventricle Act 
Independently of Each Other. 37 

CHAPTER VII. 

Premature Contractions. 

Instances in which the Auricle or the Ventricle Acts 
out of Time. 40 

CHAPTER VIII. 

Simple Paroxysmal Tachycardia. .. 47 

CHAPTER IX. 

Auricular Flutter 

Instances of Very Rapid Action of the Auricle. 52 

• • 

Vll 












Vlll 


CONTENTS 


CHAPTER X. 

Auriculae Fibrillation 

Instances of Trembling Paralysis of the Auricle. 55 

CHAPTER XI. 

Alternation of the Pulse. 59 

CHAPTER XII. 

The Effect of Valvular Disease on the Heart as Shown 
by the Electrocardiogram. 62 

CHAPTER XIII. 

Lesions in the Right Bundle Branch.64 

CHAPTER XIV. 

The Electrocardiogram as Showing Relative Activity Be¬ 
tween the Right and Left Sides of the Heart. 71 

CHAPTER XV. 

Practical Value of the Electrocardiogram. 75 

APPENDIX 

The Practical Employment of the Electrocardiograph 

CHAPTER I. 

The Setting Up of an Electrocardiographic Machine. . . 77 

CHAPTER II. 

Running the Machine. 85 

CHAPTER III. 

Correct Operation of Running the Machine with the 
Patient Connected. 88 

Index . 95 











A Key to the Electrocardiogram 


CHAPTER I 

USE OF GRAPHIC METHODS AND HISTORY 
OF THE ELECTROCARDIOGRAPH 

The average physician, on seeing the electrocardiogram of a 
person for the first time, is apt to avoid giving it any attention, 
just as he would refrain from spending time in gazing at the 
letters of the alphabet of a strange tongue. He is satisfied that 
the tracing bears significance for the initiated, just as the 
unknown symbols hold a meaning for those who are accustomed 
to speak the language they represent, but, for his part, he feels 
that he must content himself with more familiar matters and 
leave hieroglyphics for those who are expert in deciphering 
them, so he turns over the pages on which they are inscribed 
and has to take for granted whatever he is told as to their 
signification. 

This is the impression that I have received time and again 
when attempting to lecture to a medical audience on the use 
of the graphic methods of electrocardiography, and it has 
struck me that the reason is that a great many workers have 
not grasped what a graphic method really is and how its terms 
may be applied in many different branches of learning and 
practice. In other words, the graphic method is not so much 
a distinct language which, like Chaldean bricks can only be 
painfully picked out by the savant, but it is a sort of easy uni¬ 
versal key, a sign writing, in which all tongues can be read, 
and all kinds of activity described in such a form that he who 
runs may read. 

Any method of attempting to suggest the motion of some¬ 
thing which moves, by means of a picture or wavy line, is so 
elementary that it is probably as old as the human race, or as 
old as that portion of it which endeavored to convey its ideas 
by signs, and that is very old indeed. The immense conception 
of the zodiac, a line which first rises above and then dips below 
the celestial equator, and is dotted with twelve constellations 


1 




2 


KEY TO THE ELECTROCARDIOGRAM 


in which the sun appears to sojourn, one after another, in its 
course, is nothing but a primitive attempt of the mind of man 
to chart the movements and the time element of celestial 
phenomena; and the amount of genuine observation given to 
the planetary motions in times before the dawn of science, 
should stimulate us in modern days to an equal amount of alert 
attention in recording scientific phenomena. 

Modern industry owes its unparalleled growth to the fact 
that is has harnessed to its use all the discoveries, devices, and 
methods which science can achieve. The great pioneer indus¬ 
trial firms rely on the findings of research laboratories, which 
they maintain solely for the purpose of working out secrets of 
eliminating waste and furthering progress. When they try 
out a new method they want to find out what its results are; 
when they employ a large number of workmen they want to 
measure and appraise exactly what the output of labor 
is. In other words, a “record of performance” is needed, and 
to obtain this, graphic instruments are installed, equipped with 
electrical meters which give a precise charting from hour to 
hour and from day to day of the amount actually achieved. It 
the result falls short of what it should be the record shows the 
weak spots upon which attention should be concentrated. The 
meter cannot cure the symptoms, but it can read the pulse, and 
it is for the specialist in industry, as it is for his brother in 
medicine, to prescribe the treatment. An everyday example 
of the application of such a graphic method in dealing with the 
vitality of an industrial pulse is shown in the following manner. 
In a large manufacturing corporation which made use of a 
system of electrically driven motors it was noted that there 
was a daily lag in output so that the products were less in 
quantity than they should be. A graphic instrument, put to 
work, recorded a lag in output every morning when the work¬ 
men came in and started their work. It took an hour for them 
to get the motors running full speed; again at noon in antici¬ 
pation of the lunch hour, the workmen fell off in their efforts; 
in the same way they slackened down before closing time. 
When the cause of the diminished output was “placed” and 
recorded on the chart at the time of its occurrence, it was an 
easy matter to correct it. 


HISTORY OF THE ELECTROCARDIOGRAPH 


3 


When we come to the use of the graphic chart in medicine, 
one of the simplest and most commonly used is the tempera¬ 
ture chart. True, it is traced by hand from day to day, and 
not from one fraction to another by an electrical instrument, 
as is the case with the electrocardiograph, but none the less the 
analogy is not a very distant one. Both charts have a time fac¬ 
tor and a “record of performance” in relation to the time 
charted. The temperature chart expresses a picture of the 
body’s combustion processes; a steady, moderate flame in 
health, a raging furnace in conditions which are wasting the 
body’s resources, and a dull ember in enfeebled and senile con¬ 
ditions. The temperature chart is so characteristic of the bal¬ 
ance of the patient’s forces that the first thing a physician does 
when called to the bedside is to examine it and see what its 
sign language spells for him. Certain types of ups and downs 
mean a definite thing to his mind as he has been taught by long 
experience to associate a particular appearance of the line with 
a certain pathological condition, and a glance at the ‘ ‘ sign writ¬ 
ing” gives him an insight into the sufferer’s illness. 

The use of the hand-traced graphic chart is so common in all 
branches of medicine and allied sciences that it is only neces¬ 
sary to mention such different instances as the weight and feed¬ 
ing charts for infants; percentage curves showing relation of 
suicide or of insanity to economic stress, and the striking charts 
with the towering rise and gradual decline by which epidemio¬ 
logists trace the successive waves of epidemics, to appreciate 
the readiness with which this type of symbolism may be applied 
in all fields of observation. 

When we come to the use of the graphic chart in electrocar¬ 
diography, we have a system which is very much akin to that 
used by engineers in making an estimation of an electric motor, 
or of the conditions and output of a power station. In such 
graphs the various factors of voltage, power, load, friction, or 
interruption to service are taken into account. Tests are made 
with the motors under load so that any possible detrimental 
factors may be determined and shown up in the chart. 

The study of the heart is literally one of a very complicated 
motor and one which was designed to conform with very extra¬ 
ordinary specifications. When we consider that it is one which 
has to be confined within a very small space; that it must be 


4 


KEY TO THE ELECTROCARDIOGRAM 


quiet, frictionless, self-starting, and self-adjusting, so that it 
may respond instantly to calls for heavier work and yet be cap¬ 
able of slackening down when the demand is lessened; that it 
must furnish its own repair material and apply repairs without 
for a moment stopping the machinery or becoming disconnected 
from the load; that it must be in order and working day and 
night for the whole lifetime of a man, sometimes as long as 
one hundred years; we can see that it is a machine which far 
surpasses the most powerful and complex which has ever been 
designed by man. Is it any wonder then that the records of 
such complex activity are very striking and yet somewhat diffi¬ 
cult to interpret? Compared with the variations which mark 
a chart for the study of the electrical engineer, they must pre¬ 
sent a number of factors of which he does not have to take any 
account. The instruments of precision which trace the phe¬ 
nomena of the heart’s activity must also be of extreme delicacy 
in order to trace graphically the electrical discharges which 
are generated in the human motor itself. The sign language 
of electrocardiography while very striking, therefore, is more 
or less difficult, and its final interpretation has by no means 
been made, although to the expert student of these charts, as 
to the physician who estimates a disease from the look of the 
temperature chart, there are certain characteristic tracings 
which give a clue to the sufferer’s symptoms. Let it be 
emphasized, however, that interpretation of the tracings is to 
be fortified by long experience, and the whole clinical picture 
of a man must be taken into consideration when studying his 
electrocardiogram. 

The profession is always seeking for rule of thumb methods 
by which a certain diagnosis can be declared, because a patient 
showed such and such a sign. McBurney’s point in appendi¬ 
citis is a favorite of long standing, although there are some 
detractors who claim that a man must know something else 
about the patient before he diagnoses acute appendicitis and 
advises an operation. It must be acknowledged that in electro¬ 
cardiography such plainly marked signals have not yet been 
developed, and I do not believe that they ever will be, because 
clinical knowledge, imagination, and experience have always to 
be put into the balance when judging the relation of the electro¬ 
cardiogram to a man’s condition. 


HISTORY OF THE ELECTROCARDIOGRAPH 


5 

\\ lien we come to search for the commencement of the ideas 
that led to the development of modern cardiography, we find 
that, like many famous persons and well known discoveries, it 
has had its origin in very lowly circumstances. A humble 
happening observed by a man of genius, however, often gives 
rise to conclusions which transform the thought of the world. 
The apple which plumped down beside recumbent Newton is 
an example. “Relativity” may have been suggested by seeing 
a pup chase its own tail. The conception of electrocardio¬ 
graphy really took place when Galvani, early in the 18tli cen¬ 
tury, made the simple observation that frogs’ legs could be 
moved by the discharge of a small amount of electricity which 
he had accumulated in a small storage battery. So direct is 
the relationship of the modern instrument to this discovery 
that it is acknowledged in the phrase “string galvanometer,” 
a term very often used to describe the electrocardiograph. 
Galvani was able, by a very simple experiment, to show the 

connection between muscular activity and electricitv. Liter- 

«/ «/ 

ally, he made the frog’s legs jump, without the frog. He hung 
frog’s legs on an iron railing, so that one end of the muscles 
was well grounded, and allowed the spark to escape into the 
legs, which thereupon gave a violent and life-like jerk. This 
very clearly showed that the “kick” in the frog’s leg may be 
caused by electrical currents. Furthermore, all muscle when 
it contracts produces a current of its own. 

At a very much later day in the history of science, Dubois- 
Ravmond found that electrical currents from the outside were 
not the only evidence of electricitv in muscular contraction, 
but that the very action of contraction itself generated a minute 
electrical current. This current is caused because all parts of 
the muscle do not contract at the same time and the current 
flows from the contracted to the relaxed fibers. Such a current 
is generated by the motion of the muscle in the same way as 
the electricity of the self-starter of an automobile is generated 
when the car is running. Thus, currents are continually manu¬ 
factured in the body by muscle contractions and even by secret¬ 
ing cells. For that matter, all tissue cells in their very process 
of living produce electrical currents through transformations 
which are always taking place. 

These discoveries are all due to the perfection of instruments 


6 


KEY TO THE ELECTROCARDIOGRAM 


capable of detecting such minute changes. The galvanometer, 
of which countless models have been constructed, is the most 
important by far. It is capable of detecting and measuring 
electric currents and it is a specialized modification of this 
common instrument, attained after years of study and research, 
that enables the physician to diagnose accurately and treat 
his suffering heart patients. In \ T iew of the fact that such 
a large percentage of chronic afflictions is due to cardiac 
disorders, this instrument, namely the electrocardiograph, is 
becoming one of the common diagnostic measures of modern 
medicine. 

The principle of this perfected machine depends upon the 
fact that if a current is passed through a wire which is placed 
between two poles of a magnet, the wire will be deflected one 
way or the other, according to the direction of the current pass¬ 
ing through it. The currents, in this case, are generated by 
the heart. As this organ goes through a series of contractions 
the currents which produce the waves in the wire are measured 
bv the size and duration of the waves, and recorded on a chart 
ruled both horizontally and vertically for that purpose, which 
will be explained in detail later on. 

Since the heart lies obliquely in the body the distribution of 
the currents given off is not symmetrical, but is always recorded 
from the arms and left leg. From here, wires lead to the string 
of the galvanometer, between the magnets. The wires carry 
the heart currents and the currents deflect the wire. The two 
wires at any time leading to the string of the instrument are 
called ‘ ‘ a Lead. ’ ’ 

The question is often asked as to why, in making electro¬ 
cardiographic tracings, the wires are attached to both arms 
and to only the left leg. The reason for this is that the apex of 
the heart points toward the left in regard to the trunk, so that 
the best lines for observation of the differences of potential are: 

(1) across the top of the heart, between the two arms; 

(2) the axis of the heart, be ween the right arm and left leg; 

(3) the left side of the heart, between the left arm and left leg. 
If the right leg were used the line between the right arm and 
right leg would not cross the heart at all, neither would an ob¬ 
servation from a line taken from one leg to the other directly 
cross the heart. In those rare cases of transposition of viscera 


HISTORY OF THE ELECTROCARDIOGRAPH i 

where the heart points to the right, we naturally take our ob¬ 
servations with leads which correspond to the altered position.* 
Another inquiry which is often made is why it is necessary to 
have three leads, and in what way the leads differ. It should be 
stated that different parts of the heart attain different degrees 
of potential during the beat. The leads are as follows: 


Lead I.Current from right arm and left arm; 

Lead II.Current from right arm and left leg; 

Lead III.Current from left arm and left leg. 


In the normal individual the three leads have somewhat 
different values. There is, however, a considerable latitude of 
variation in the waves of all the leads without going outside the 
limits of the normal, so that we can repeat that no hard and fast 
rule can be laid down as to what is a “normal” electrocardi¬ 
ogram. The curve must be normal for the individual when all 
clinical data are duly considered. 

In regard to the heart currents which are carried by the leads 
to the galvanometer, one must realize that they are extremely 
minute and that the wire which is sensitive to them must be of 
extreme delicacy. It is so fine, indeed, that it can scarcely be 
seen by the naked eye and measures barely the width of a red 
blood corpuscle. It is, however, so sturdy and flexible that it 
may readily be adjusted by means of infinitely larger electric 
currents than those generated by the heart. Thus the sensitive¬ 
ness of the string can be tested at any given moment. This can 
be varied by increasing or lessening the tension of the wire by 
means of a micrometer screw. It is usual so to adjust the string 
that a passage of one millivolt of current makes a deflection of 
one centimeter in the shadow. The movements of the string 
are photographed on a revolving film, which, when developed, 
gives us an electrocardiogram, or, in other words, a true heart 
autograph. 

In general it may be said that observations of the electric 
currents collected across the top of the heart are more affected 
by the activities of the upper pole of the heart (Lead I) ; that 
the observations taken in the axis of the heart (Lead II) are 
indicative of the general activity of the heart as a whole; and 
that the observations taken of the left side of the heart (Lead 
III) are essentially influenced by the left ventricle. This is well 


* Dextrocardia causes inversion of all waves in Lead I, including P. 







Fig.— 1 . —Diagram illustrating the origin in the heart of the three currents giving 
rise to the three Leads of the electrocardiogram. 



















































HISTORY OF THE ELECTROCARDIOGRAPH 


9 


illustrated by the difference easily noted in the leads, in that 
the upper pole gives the upward R wave; observation of the 
axis of the heart gives a lower R wave; and when the left 
ventricle is enlarged the tracing of the left side of the heart 
gives a downward wave (S). 

A thing which is very hard to understand is that electrocardi¬ 
ographic tracings are really a record of the variations in poten¬ 
tial between various parts of the heart. There is probably 
no particular current flowing along in the direction in which 
we measure it, but when we connect different parts of the heart 
which have a different potential, current does flow. The activi¬ 
ties of the heart create differences of electric potential in differ¬ 
ent places and we observe them and interpret them as best we 
can. This explains definitely why we are able to measure the 
relative activity of different chambers of the heart, such as the 
right and left ventricles, when we refer the activities to a stan- 

i 

dard set of leads. 

Since the time when the electrocardiograph was first worked 
out by Adler in 1897, and later perfected by Eintlioven, many 
refinements of the instrument have taken place. One of the 
earliest was the discovery, by Eintlioven himself, that the 
heart’s currents may be carried through wires for a long dis¬ 
tance. In his laboratory at Leyden electrocardiograms were 
made on patients in a hospital a mile or more away. This 
revelation has made the use of the electrocardiograph eminently 
practical in hospitals where ward beds can be wired and the 
heart action of patients lying in their ward beds be recorded in 
the electrocardiographic room. 

A device was used by Siemans and Halske wherein a coil, 
with a minute mirror attached, was used between the poles of 
the magnet instead of a straight filament. The heart currents 
caused a rotation of the mirror to one side or the other and a 
reflected beam of light was recorded as a result. This instru¬ 
ment is not used in this country, but it is preferred by many 
foreign investigators because the coil does not require as deli¬ 
cate adjustment as the filament. 

On the same principle as the electrocardiograph it was found 
that vibrations caused by the heart’s sounds could likewise be 
electrically recorded. Therefore, two wires, one for the heart 
action and one for the heart sound, may be inserted between the 


10 


KEY TO THE ELECTROCARDIOGRAM 


magnetic poles and a picture of each recorded. Although such 
photographs are very valuable in some instances, it requires 
careful and expert manipulation to keep the strings independent 
of each other. 

Many ingenious devices have, from time to time, been used 
along with the electrocardiograph, such as the photograph of 
the blood pressure measurements and the respiratory rate and 
size of excursions. The possibility of other devices and refine¬ 
ments is endless. Recently an article appeared in a popular 
scientific paper in which this machine was proposed to make 
records in the detection of crime. 

In the electrocardiograph, therefore, the heart writes its own 
story, and thus, indirectly the story of the whole body. As a 
result electro-medical science has attained an undreamed of 
state of exactitude, the glory of which is that this instrument 
is not a mere delicate plaything of the laboratory investigator 
but a hard worked, everyday tool of the modern clinician. 

A final word of caution must be added against an over confi¬ 
dence in complete diagnosis by means of the electrocardiogram. 
Like a great many other expert laboratory tests, it does not 
replace clinical examination, and should be used only to verify 
and corroborate a careful general observation of the patient. 
There are many obscure heart conditions in which the diagnosis 
would remain in doubt without the employment of the electro¬ 
cardiograph. It should be taken on several successive occasions 
and under different conditions, in order to eliminate any possible 
errors due to extraneous influences. The disturbances produced 
by nervousness, fatigue, and exertion can thus be given their 
due value in estimating the patient’s general condition. Used 
thus, carefully and methodically, the electrocardiogram is a re¬ 
cord of great precision and diagnostic value in the recording of 
cardiac disturbances or alterations. 

In concluding this chapter I would like to quote what Dr. 
John Hay says in this connection: In his book entitled 4 ‘ Graphic 
Methods in Heart Disease” he deals with the question of the 
practical value of cardiography to the average physician. 
He says “I can imagine a practitioner asking how the investi¬ 
gation of the action of the heart by these methods can be helpful 
to him in his practice. The answer is that it creates a new 
interest. His knowledge of the heart becomes more concise. 


HISTORY OF THE ELECTROCARDIOGRAPH 


11 


He is no longer satisfied with a sloppy diagnosis such as 
‘irregular action of the heart,’ but is able to define clearly the 
nature of the irregularity. He is constantly checking and cor¬ 
recting his diagnoses based on the ordinary clinical exam¬ 
ination. 

“As his diagnosis becomes more correct, there is a correspond¬ 
ing clarity in his prognosis. He speaks of the future with 
more confidence. The various deviations from the normal are 
appreciated at their proper value. He no longer penalises an 
applicant for insurance because of an occasional extra-systole, 
nor does he blight a boy’s school life because of a sinus 
arrhythmia. An extra-systole which unmasks an alternating 
pulse is to him full of grave significance, for he recognizes that 
it may be the first indication of impending disaster. His mind 
ceases to be a hazy fog in regard to auricular fibrillation. Every 
day he is dealing with this serious complication of the disabled 
heart, and gradually he acquires an accurate knowledge of the 
diagnosis, prognosis, and treatment. Heart-block ceases to be 
a mystery, and he welcomes the opportunity of analyzing a case 
of rapid heart action. 

“He learns when it is essential that the ordinary methods of 
clinical investigation should be supplemented with the informa¬ 
tion which can only be supplied by the polygraph or electro¬ 
cardiograph. And he will gradually find that he becomes less 
and less dependent on these instruments with which he has 
served an apprenticeship, for he has educated himself to do 
without them. His fingers, his eyes, and his ears are enough in 
themselves. He has made an advance as a clinician.” 

Thus the only proper qualification for the practice of cardi¬ 
ology without instruments of precision is a long use of them. 
But the man who has gotten to know them never willingly gives 
them up. 


CHAPTER II 


THE ELECTRIC AUTOGRAPH OF THE HEART 
OF A HEALTHY PERSON 

It should be remembered that the electrocardiogram is an 
autograph and that, like the autograph of a person, it always 
differs from the autograph of every other person. This does 
not mean, however, that the autograph of an average normal 
individual cannot be told from that of an ignorant, illiterate 
or very aged person. 

To understand the normal electric autograph it is necessary 
to comprehend the true nature of the heart beat. The heart beat 
and the heart sounds do not correspond because some of the most 
important events in the heart do not make any noise and some 
of the least important give loud sounds. 

The two sounds of the heart are caused by the thud of the 
ventricle when it begins to contract and the closure of the 
aortic valves when it begins to expand. The auricle makes no 
sound and after the heart suddenly begins to contract the 
ventricle makes no further noise. 

However, every activity of the heart is recorded in the elec¬ 
trocardiogram as it happens. The heart action is found to 
divide itself into three principal parts: 

(1) The auricles contract (P wave), and gently push the 

blood into the ventricles. 

(2) The mitral and tricuspid valves close; the ventricles con¬ 

tract firmly, suddenly opening the aortic valve, and 
take a grip on the blood contained in the ventricle 
(R wave). 

(3) The ventricles proceed to squeeze the blood out of the 

heart into the pulmonary artery and aorta (T wave). 

When the ventricle takes its sudden grip on its contents a 
sharp electric current is generated. This is recorded in the 
electrocardiogram as the R wave. The reason that this is a 
sharp, intense current is due to the fact that fluid cannot be 
moved suddenly. If you have ever jumped from a high place 
and landed flat on the water you have discovered this fact. 

12 


THE ELECTRIC AUTOGRAPH OF THE HEART 


13 


A little later tlie water moved and yon sank; but at the moment 
of contact the water did not feel as if it were going to move. 

When the ventricle has contracted on its contents, it proceeds 
to perform its real work in a much more gradual way and to 
squeeze the blood into the circulation. This work of the ven¬ 
tricle is recorded by the T wave. Therefore, just as a person 
in signing his name writes his given name first, then his middle 
name and finally his surname, the heart, through its electric 
current, writes in the electrocardiogram its P, R, and T—its 
auricular and ventricular activities, and its ventricular contrac¬ 
tion. 

The waves of the electrocardiogram are denoted in an arbi¬ 
trary manner by certain letters. It was decided to take a series 
of letters at the end of the alphabet, namely, P, Q, R, S, T, U, 
to represent certain waves found in the electrocardiogram. 



Fig. 2.—Scheme of the normal electrocardiogram. 


These letters cover all the large and small currents that can 
occur in the electrocardiogram of all healthy people. Some 
persons write their names on the line, others above, and then 
again some write below the line. In the same manner some 
electrocardiograms have the Q waves (between the P wave and 
the R wave) going below the line, and the S wave (between the 
R wave and the T wave) also below the line. Occasionally there 
is a U wave after the T wave—a final flourish, as it were. 

I have spoken above of the normal electrocardiogram. This 
is a statement which I must not let pass without some qualifi¬ 
cation, because if I were to speak to you about a person with a 




14 


KEY TO THE ELECTROCARDIOGRAM 


“normal face 1 ’ you would burst out laughing and say “Doctor, 
wliat do you mean by a normal face?” The fact is that there are 
as many varieties of faces as there are of inhabitants on the 
globe, and there are racial variations as well as individual ones, 
so that what is a normal face for a Chinaman may be strikingly 
unusual in one of New York’s four hundred. The same may be 
said of the manifold variations of electrocardiograms. The 
question is whether the electrocardiogram is normal for an indi¬ 
vidual in all his relations, and for this reason this expression 
of the heart’s activities is never a complete interpretation, but 
only a relative one, which must be considered with all the other 
factors of a person’s physical and mental make-up. 

Before passing on to the consideration of variations which 
are frequently seen in association with distinctly abnormal con¬ 
ditions, let us recapitulate the knowledge we have acquired as 
to the titles of the waves and what they represent. To borrow 
a phrase from our old friend Euclid let us say “Let P be the 
activity of the auricle.” 

Schema of Waves 

P up or down, 

Q always down, 

R always up, 

S always down, 

T up or down. 


The base line is the shadow of the string when no electricity 
is passing through it. 

When electricity is passing through the string, that is when 
the excitation impulse is being recorded as it passes in its due 
course from one portion of the heart to the other: 

First 

The auricle contracts (au- which is usually a little 

ricular systole) and makes mound above the base line, 

the P wave sometimes a cup below it. 

It can be up or down. 

Second 


The ventricle becomes ac- a little downward dip, not 
tive; sometimes it causes always seen, but when pres- 

tlie Q wave ent leading up to 


THE ELECTRIC AUTOGRAPH OF THE HEART 


15 


Third 

The chief activity of the 
ventricle, represented by 

the R wave 

Fourth 

The wall of the steeple 
plunges below the base 
line again and makes 

the S wave 

Fifth 

the curve which represents 
the final activity of the 
ventricle, and is called 

the T wave 


which makes a c h u r c h 
steeple-like wave, always 
above the line, then 

always below the line, and 
sometimes this S wave is all 
of the ventricular activity 
shown, then comes 

this may be either up or 
down. 


Finally 

there is occasionally the U wave this pertains to diastole. 

From T to the following P is the diastolic period. 

When there is a long steeple-like wave below the line, it is 
not a reversed R wave but an exaggerated S wave, the R wave 
at the same time being stunted. 

It may be stated here that the minor waves are of very little 
significance in studying the electric autograph. Almost all the 
advantage of the study is obtained from the P, R, and T waves. 
In a healthy person the beat of the heart commences in the 
auricle which contracts, and pushes the blood into the ventricle. 
The ventricle contracts sharply on the blood contained in it and 
further contracts more slowly to drive the blood into the 
circulation. These events come regularly in sequence and are 
recorded by the P, R, and T waves. 

When we have clearly grasped the various letters of which 
the autograph is composed, let us turn to the grouping and see 
if we cannot read the message and signature of the heart as it 
is inscribed. In other words, the curves are written for us, 
what can we make of them? We shall do very much better if 
we proceed to spell them out syllable by syllable in an orderly 
manner. 

The Significance of the Downward T Wave. In describing 
the waves, it has been stated that the P wave may be up or 
down, that the R wave is always up, because when it appears to 
go down, it is another thing, being the S wave. But the T wave, 


16 


KEY TO THE ELECTROCARDIOGRAM 


like the P wave may be up or down. Downward T wave lias 
a special significance, particularly when it occurs in the fiist or 
second leads, and parenthetically it may be remarked that the 
downward T wave constitutes a variation in the electrocardio¬ 
gram that can never be overlooked or made light of. In the 



Fig. 3.—Diagram illustrating the heart action shown hy the three principal 
waves (P, R, and T). P represents the contraction of the auricles, R the first 
sharp contraction of the ventricle, and T the further slower contraction of the 
ventricle driving the blood into the circulation. 


same way an abnormal Q, R, S complex is always entitled to 
very careful consideration. 

The person with a downward T wave in the first and second 
leads is one requiring a most careful treatment and is subject 











































































THE ELECTRIC AUTOGRAPH OF THE HEART 


17 


to serious heart attacks. On the other hand the absence of the 
downward T wave is not a guarantee of the integrity of the 
heart; so the sign is a positive and not a negative one. 

It must always be remembered that a negative T wave in 
Lead III is common in healthy hearts and also that a downward 
T wave in people who have taken digitalis within a few weeks 
may be due to that. 

The downward T wave in the first lead is often seen in the 
hearts of people suffering from angina pectoris and aortic val¬ 
vular disease. The downward T waves in the first and second 
leads are very frequent indeed in people who carry a very high 
blood pressure. Here the condition is one of over-work of the 
heart. The downward T wave in Lead II and not in Lead I is 
not as serious an indication as when it occurs in Lead I or in 
Leads I and II, but nevertheless it is found in very much the 
same type of condition when it does occur. As the T wave is 
normally negative in Lead III in many people it can be dis¬ 
regarded and the examples where the three leads show the T 
wave downward, are considered of the same significance as 
when only Leads I and II are involved. 

The negative T wave is not necessarily evidence of change 
in the heart tissue but it does prove the presence of functional 
change and it is a strong indication for careful treatment and 
continuous observation. 

When the abnormal downward T wave is found in com¬ 
bination with partial or complete heart block it adds to the 
importance of the condition. 

In studying the tracings produced we can take in order the 
following points: First, the heart heat , in regard to its rate 
and regularity or irregularity. Regularity of the heart is shown 
by even spacing of the distance between successive R waves. 
If these spaces are unequal, irregularity of the heart beat is 
evidenced. Second, the heart rate. The chart is marked by 
vertical lines, or abscissae, which measure the events of the 
cardiac cycle in regard to time. To procure the heart rate 
count 30 abscissae, representing 1/5 second each, and multiply 
the number of cycles (complete beats) in that space by 10. If 
there is part of a cycle over, reduce it to fifths of a cycle and 
add it to the result; e. g. 6J = 62. 


18 


KEY TO THE ELECTROCARDIOGRAM 


The reading of the leads is the next step to be achieved. 
As we have said, Lead II is first in importance in the informa¬ 
tion it conveys, but a comparison of the other leads is also 
necessary. In reading Lead II the deviations and sequence 
of the waves are to be noted: (1) the P-R-T sequence; is this 
normal? (2) the P wave; is this disturbed? (3) the P-R 
interval; what is its length, and is the length regular? (4) 
the R wave, note any distortions; (5) the T wave; is it up or 
down ? 

After careful examination of Lead II a comparison of all 
three leads is to be made. In examining all three leads as a 
whole, a low amplitude of the waves sometimes expresses a 
low state of contraction impulse. This must be watched for. 
The preponderance of one ventricle or the other can be diag¬ 
nosed by comparison of the leads. In left ventricular pre¬ 
ponderance the tall R waves, or steeples, tend to turn away 
from each other in Lead I and Lead III; and this is also the 
case in right bundle-brancli-block. The latter however, shows 
a wide R, followed by a curve in two directions. The opposite 
condition obtains in right ventricular preponderance and in 
left bundle-brancli-block. In these cases the steeples tend to 
lean towards each other in Leads I and III. 

It would be well here to refer to the method of ruling and 
taking measurements in the electrocardiographic chart. Briefly 
it may be described as a checkerboard ruling of fine lines 
across which travels the wavy shadow of the string, in a gen¬ 
eral horizontal direction. Both the vertical and the horizontal 
ruling have their significance. The horizontal lines, or ordi¬ 
nates, are engraved on the camera lens. These lines represent 
millivolts, and the force of the wave as it rises up to a certain 
height, or plunges to a certain depth, is called its amplitude. 
Each ruled space represents 0.1 millivolt. 

The Time Record: A set of vertical lines crosses the chart, 
by which time is measured. These are called abscissae. Each 
space equals 0.04 second. Every fifth line is usually thicker 
and occurs each 0.20 (1/5) second. These lines are caused by 
the shadows of regularly revolving spokes, photographed on the 
record. 

The String: Upon this crosswise ruling of lines lies the 
heavy line caused by the shadow of the string, horizontal when 


THE ELECTRIC AUTOGRAPH OF THE HEART 


19 


at rest, and taking wave forms when agitated by electric 
currents. 

Normal Limits of Waves: Each typical heart wave has its 
normal amplitude and normal width (time). If this is trans¬ 
cended it indicates either exaggerated or delayed activity at 
some point in the heart. 


Width. 
0.08 second 
0.12 to 0.18 second 


0.1 second 


Height. 

P wave normally up to 2 mm. 

P-R interval 

Q (when present) about 2 mm. 

R wave 10 to 20 mm. 

S (when present) 2 to 4 mm. 

T wave 2 to 4 mm. 

We have now studied the plan of ruling of the chart and 
examined in detail the kinds of waves to be found upon it and 
the order in which they may be expected to occur, also the 
direction up and down, the height of the climb or depth of the 
drop, and the duration of the wave on the string. An approxi¬ 
mate normal has been given for these factors, although it must 
never be forgotten that there is a considerable variation in 
electrocardiograms without our being able to say that they lie 
outside of the domain of the normal. Respiration, exertion, 
and the position of the heart in the thoracic cavity all have a 
modifying influence. 

When we come, however, to the study of autographs of dis¬ 
ordered hearts, very striking peculiarities will be seen which 
could not in any way be recognized as a normal mode of 
signature. It is well to examine these tracings with as much 
caution as the cashier in a bank peruses a client’s signature 
on a check, when it has suddenly undergone an alteration 
which makes it look unfamiliar. It is the same, yet not the 
same, and he is puzzled as to its authenticity. Let us suppose 
that a well known business man who has been accustomed to 
signing a number of important checks, and having them honored 
by the bank, is suddenly bereft of reason, and his handwriting 
undergoes some eccentric changes. The checks begin to pass 
to the bank and the cashier is astounded to see the well known 
signature of John Smith written with the J upside down and 
the S turned the wrong way. He realizes at once that some¬ 
thing very unusual has occurred and dares not pass the check 


20 


KEY TO THE ELECTROCARDIOGRAM 


without consulting the manager. The chief has just received 
word that John Smith has been removed to a sanitarium, suffer¬ 
ing from nervous breakdown from overwork, and that his 
financial dealings are not to be considered reliable. The 
peculiarity of the situation is thus explained and the bank is 
absolved from responsibility. 

In the same way eccentricities will be shown when electric 
autographs of disordered hearts are examined, and among the 
first things discovered will be the fact that certain hearts show 
a long, sharp wave resembling the R wave, but it dives below 
the line in the opposite direction. This wave is not preceded 
by any small wave, as is found in the natural heart beat to rep¬ 
resent the contraction of the auricle; but it comes at a time 
when the heart is supposed to be resting and nothing should 
occur. The question is: Why is this wave in the opposite direc¬ 
tion to the natural wave of the same shape that we have 
become accustomed to as a natural part of the picture! The 
answer is that ordinary conditions have become reversed. 
Usually the muscles begin to contract at one end and the con¬ 
traction wave travels along the muscle till it reaches the other 
end, and as it does so it generates a current in the opposite 
direction. The normal thing is for the wave of contraction to 
commence in the top of the ventricle and travel toward the 
point of the heart, and this activity produces an electric cur¬ 
rent which causes a wave above the line. When, however, the 
wave of contraction starts near the apex of the ventricle and 
travels toward its base, it produces a current in what we might 
call the wrong direction. There is no evidence that the beat 
started in the auricle before it reached the ventricle. In fact 
it did not commence in the auricle. The ventricle has, as it 
were, like the Irishman who was 4 ‘agin the government” 
started a regime of its own, an independent performance which 
was entirely out of order. This tendency on the part of some 
portion of the heart to start somewhat anarchistic activities can 
be detected by studying the shape and direction of the waves. 
The writing will betray the fact that there is disunion of action 
in various parts of the heart and this is the first sign of the 
“kingdom divided against itself.” 

In proceeding with the study a means will be discovered 
whereby one can determine in which ventricle such an extra 


THE ELECTRIC AUTOGRAPH OF THE HEART 


•21 


beat originated and exactly what its relation is to the normal 
activity of the heart. Sometimes it is only an extra under¬ 
taking that does not influence the regular beats at all, but 
ordinarily it uses up so much of the energy of the heart that 
one of the natural beats is omitted. 

Fifty years ago a great student of the heart predicted that 
when the function of the auricle was once thoroughly under¬ 
stood the greatest advance in the knowledge of cardiology of 
the century would be accomplished. This man was very far- 
seeing and his prophecy has been fulfilled in the achievements 
of electrocardiography, the greatest of which is the interpre¬ 
tation of the relation of the auricle to the heart beat. In the 
older text-books of the heart the auricle is seldom mentioned. 
Its significance was not realized. In modern cardiology, as we 
are now studying it, the auricular activity is a very important 
element in explaining heart disorders. 

An ordered sequence of events in the heart beat is perhaps 
the most important factor in the promotion of harmonious and 
efficient activity of the organ. The heart lias a responsibility 
which can be likened to that of a ship carrying a number of 
passengers. When we think what the heart has* to do for the 
safety and preservation of all the other organs—the respira¬ 
tory, the nervous, the alimentary, and those of locomotion—to 
steer them safely on their life voyage, as it were, we can see 
that there must be a very efficientlv directed service to main- 
tain the welfare of such a cargo. The captain has to take 
charge, but he cannot do the work of the ship himself, so his 
orders travel to those next in command, and on down the line, 
each subordinate receiving his instructions, executing his part 
of the work, and passing on the word which directs the next 
man in his task. When all are working in harmony, every man 
in his own place, all is well, but if the officers become at vari¬ 
ance with the captain and take upon themselves an independent 
authority, some of the crew perhaps go with them, some with 
the captain, or some set up a lawless free lance government of 
their own. Dire confusion results, and one wonders how, under 
such conditions the ship makes port. Try to imagine the heart 
as sailing under regular orders which best promote its safety 
and efficiency. 

The heart beat should begin in the auricle in a regular con- 




KEY TO THE ELECTROCARDIOGRAM 



traction occurring about seventy-two times a minute and should 
spread in an orderly manner to the ventricles. If there is any 
pathological departure from the normal routine it may be 
shown in the waves in four ways, viz., sequence, amplitude, 
direction, and duration. In the case of anv serious structural 
change in the heart between the auricles and the ventricles, the 
orderly spread of the impulse is interfered with. If this inter¬ 
ference is extreme the impulse does not pass at all and as a 
result the auricle and the ventricle beat like separate organs. 
In this case the rate of the ventricle is about twenty-eight per 
minute and the rate of the auricle seventy-five or more. In the 
records which we shall have to show of this condition the P 
waves (auricular activity) appear in perfect order and the R 
and T waves (ventricular activity) are shown in normal 
seqence, but without any time relation to the auricle. 

Sometimes the auricle is paralyzed and does not produce any 
one large contraction wave. Ordinarily this paralysis is of a 
trembling type and generates a great many very small impulses 
and causes quite a number of small currents. This again is 
excellently shown in the electrocardiogram. In other instances 
where the auricle does not contract regularly, it seems to fall 
under the influence of the nerves of respiration. This incident 
is very frequent in children. The knowledge of this fact has 
made it possible to give liberty to many children supposed to 
have inflammation of the heart when, in reality, they have 
nothing of the sort. 

Before closing this chapter in which we have explained at 
some length the groundwork of electrocardiography, in a 
manner which we hope will induce the physician to take suffic¬ 
ient interest to delve into its interesting questions for himself, 
let us try to answer a very practical question, namely, What is 
its actual clinical value to the average physician, and to what 
extent can he rely on it ? 

The electrocardiogram has greatly advanced the discovery 
and certainty of diagnosis of cardiac conditions. In such con¬ 
ditions as cardiac enlargement it is possible to discover which 
chamber of the heart is the predominant one. Confirmatory 
diagnosis can be obtained in such conditions as mitral stenosis, 
aortic valvular disease and congenital heart troubles. The pro¬ 
gress of the patient when taking certain cardiac remedies 


THE ELECTRIC AUTOGRAPH OF THE HEART 


23 


can be appraised by the electrocardiogram, and the physiologic 
tolerance of such drugs estimated. The condition of the heart 
when affected by acute infectious illness can be studied, as also 
its functional activity and alterations in structure of the myo- 
cardium, by records taken at intervals over a long period of 
time. Many atypical conditions and arrhythmias can be strik¬ 
ingly illustrated by the electrocardiogram as in no other way. 

Many obscure cardiac conditions need the enlightenment 
which is shed by the electrocardiogram before they can be duly 
recognized and the proper treatment instituted. Carefully 
repeated records, taken from time to time and under different 
conditions of stress or physical variation, are necessary for the 
well grounded study of the heart in all its aspects. 

At times the auricle takes on a very rapid and regular action 
which is so quick that the ventricle is not able to respond, and 
therefore answers to only every other contraction or every third 
contraction of the auricle. There are also the types of hearts 
that beat rapidly at inconvenient times and cause people to say 
that they are suffering from palpitation. Sometimes this is 
the fault of the auricle and then again it may be that of the ven¬ 
tricle. When the electric picture of the heart is carefully 
studied all these things become perfectly clear. 

We have seen that altered direction of the waves is one of the 
abnormalities, which is seen in the charts of disordered action. 
Some of these alterations of direction which may be noted are: 
inversion of all waves in Lead I, signifying dextrocardia (very 
rare) ; (2) right ventricular premature beat, as indicated by a 
premature K wave, positive and usually notched, seen in 
Lead II; (3) left ventricular premature beat, negative in Lead 
II; (4) premature auricular contractions is shown by a prema¬ 
ture P wave, and often one that has an altered shape. 


CHAPTER III 


THE TIME ELEMENT IN THE ELECTROCARDIOGRAM 

We saw in Chapter II, pp. 17 and 18, that the electrocardio¬ 
gram possessed three elements, of which the time record was 
one. We will go a little more fully into the timing of events, as 
it is one of the most important factors in the picture of the heart 
beat. In fact it is just as useful for us to know that the cardiac 
events are being correctly timed, as it is for a clock upon which 
vve are depending to strike twelve, at the exact time that the 
hands are pointing to that hour. We can imagine that if the 
clock strikes at any odd time, independently of the hands, we 
could not stake much on its reliability as a timekeeper. 

In examining the pictures of the heart beat, as we have said, 
there may a wide range of variation within the limits of the 
normal; thus the shape of the picture may be altered by outside 
circumstances in such a way that the auricular wave (P wave) 
may be small or large. This is also true of the ventricular 
wave itself, as well as the wave which represents the work of 
the ventricle. Seeing that the waves may be frequently altered 
in design, it is fortunate that the time of their appearance can 
be accurately recorded on the electrocardiogram, and this is 
done by the time marker which makes a little dot or line everv 
fifth of a second or so on the picture. Without this we 
should be like people looking out of the window to see what 
time of day it was, by the height of the sun. With an accurate 
time piece the sun can peep in and out of the clouds as it 
pleases, we do not have to depend on it. Therefore, we can 
forget the shape of the drawing entirely and identify the differ¬ 
ent currents by their type and the time of their occurrence. 
That is we can measure the time that elapses between the work 
of the auricle and that of the ventricle, and when the ventricles 
lag behind the auricle, we can tell which ventricle is falling 
behind and to what extent. 

In this respect the electrocardiogram is far superior to pulse 
tracings because the wave from the auricle is recorded at the 
neck only a few inches from the heart, and the wave from the 

24 


THE TIME ELEMENT IN THE ELECTROCARDIOGRAM 


25 


ventricle is taken at the wrist, about three feet from the heart. 
1 lie measurement of the time between these two events on a 
polygraph is not perfectly reliable, as these waves travel along 
the blood current at a comparatively slow rate. Since, how¬ 
ever, an electric current can travel around the world in an 
inconceivably short time there is no appreciable difference in 
the length of time which elapses in the transmission of the cur¬ 
rent from the auricle and the ventricle. 

In a healthy person the heart beat starts in the auricle and 
from thence travels down the connection which unites the 
auricle to the ventricle. This is a very definite structure which 
is named the auriclo-ventricnlar bundle. It consists of a main 
stem which branches off toward the two ventricles, and it is 
along these branches that the impulse of the heart beat passes 
and carries its influence to the ventricles. This viaduct be¬ 
tween auricles and ventricles is rarely put out of commission, 
that is we seldom find it the seat of disease; but sometimes a 
hardening of its structures occurs and the heart beat, as it 
travels down, finds a difficulty in overcoming the obstruction to 
its passage. The electrocardiogram, which faithfully records 
any disturbance in the work of the heart, shows immediately 
that the electricity of the ventricle is much later than it should 
be after that from the auricle. This means that the impulse 
has had great difficulty in coming through at all, and this 
serious interference is spoken of as “delayed transmission.” 

u Delayed transmission” is a fact of great significance in the 
electrocardiographic examination. It is the first step of a con¬ 
dition which marks complete severing of connection in the 
sequence between the auricle and the ventricle. When the 
auricles and ventricles act independently of each other, it is 
because the impulse between them is blocked. This condition 
is known as heart block and it will be dealt with fully in a later 
chapter. 

An outside factor which can produce delayed transmission is 
the administration of large doses of digitalis. 

At this point we might recall a few points in the anatomy 
and physiology of the heart. As to anatomy, the most impor¬ 
tant structure that those who graduated in medicine ten or fif¬ 
teen years ago might be not familiar with is the so-called bun¬ 
dle of His. Many physicians get the impression that because 


26 


KEY TO THE ELECTROCARDIOGRAM 


this structure was so late in being recognized and its discovery 
was so much a matter of comment, that it is a very difficult 
structure to see. This is not true, particularly in the ox heart 
and also in the human heart, if we realize that we have been 
looking* at it all our lives without knowing it. We mention 
the ox heart because you can order an ox heart from your 
butcher and dissect it any morning you feel like it. Indeed, for 
men in practice who seldom have occasion to see the heart in 
action, it is a pleasure to re-study an animal’s heart once in a 
while. If your butcher can do so, have him get it with a good 
part of the aorta attached. Sometimes it is easier to get a 
sheep’s heart with the adjacent vessels, than to obtain a bul¬ 
lock’s heart, but the bullock’s heart being larger is better. At 
the same time that you note the bundle of His, you can also 
study carefully the beautiful workings of the valves and cham¬ 
bers. What is worth emphasizing is that the bundle of His is 
not a microscopic structure and there is nothing mysterious 
about it any more. 

In general it may be said that there are two ways to pursue 
these studies. We can, on the one hand, approach the subject 
from the purely practical point of view, adopting the best work¬ 
ing theories and avoiding special attention to matters of con¬ 
troversy, and immediately apply what we know in the care of 
our patients. Or, on the other hand, we can attempt to follow 
out electrocardiology to the last analysis which involves an 
intensive study of electricity, physiology, and pathology. For 
most men this intensive study is absolutely impractical, but 
there is no reason why one should not learn to use the facts of 
electrocardiology, just as one often speaks a foreign language 
without special knowledge of grammar. It would be a foolish 
man who starved in a foreign country while he was waiting to 
perfect his knowledge of grammar, instead of using the few 
broken sentences that he could utter for the practical purpose 
of obtaining a meal. The best method for the actual practi¬ 
tioner of medicine is to study intensively such examples of ir¬ 
regular hearts as come under his notice, making this a founda¬ 
tion for the general mastery of the subject. Any attempting to 
study the subject beginning with the complete study of physi¬ 
ology, is doomed to failure with the average man, unless he be 
a very young man under the discipline of academic control. 


CHAPTER IV 


SINUS ARRHYTHMIA 


The form of sinus arrhythmia met with in childhood is very 
naturally the type of irregularity to first claim our attention. 
Owing to the relative instabilitv of the nervous system in the 
child, as compared with the adult, the child’s heart is never 
absolutely regular. The irregularity noted it that of a varia- 



Fig. 4.—Electrocardiogram of a boy 14 years of age, showing sinus arrhythmia. 
There is no difference in the waves from one heart beat to another, but there 
is a continual variation in the spaces between the different beats. In all three 
leads, all of the waves are indicated by their letters for two heart cycles. 

tion in the spacing of the beats. Each beat is as it should be 
in itself, but there is a gradual changing in the space between 
the beats so that they tend to become nearer together, and then 
further apart. 

It is well at the outset to avoid laying over importance on 
this phenomenon. The tendency in childhood to “run a tem- 

27 




























































































28 


KEY TO THE ELECTROCARDIOGRAM 


perature” for comparatively slight cause is well known; a ther¬ 
mic chart which would in an adult give rise to uneasiness, is 
often in a child of little significance, and accompanies a diges¬ 
tive upset, over fatigue, or excitement. This is particularly 
true in nervous u fidgety’’ children. The same thing is true of 
the heart’s action. The undeveloped state of the nervous sys¬ 
tem in the child makes it prone to react to some excitement, 
out of the normal course of things, with a pulse rate which 
would represent an unusual velocity in the adult. This is par¬ 
ticularly true in regard to the doctor’s visit. The average 
child is apt to feel that his life is in danger if he does not regard 



S 



Fig. 5.—Electrocardiogram with a marked degree of sinus arrhythmia. Some 
of the long pauses are almost twice the length of the shorter ones. This record 
also shows right ventricular preponderance. 

the physician’s proceedings with suspicion, and the element of 
fear or shrinking in nervous children gives rise to a quickened 
pulse that the doctor, on his first visit cannot attribute entirely 
to disease. Quieter conditions, or a subsequent visit, will often 
show that the pulse has subsided to normal. 

Sinus arrhythmia, although quite essential in all children, 
varies greatly in the different physical types. In some, the 
irregularity is barely noticeable, whereas in others it is so 




















































































































SINUS ARRHYTHMIA 


29 


marked that it makes us wonder for a time whether a child 
with such a rhythm, can, after all, be entirely normal. Before 
the days of accurate heart measurement a child with a marked 
sinus arrhythmia was often supposed to have a grave disturb¬ 
ance of the heart and was put to bed for long periods of time, 
kept from school, and made to rest. As a result the child, 
instead of developing into a sturdy youth through play and 
exercise, became a pathetic little invalid. 

In order to be able to teach the parents of these children that 
they may safely disregard this irregularity, without risking 



Fig. 6.—Electrocardiogram demonstrating a slight degree of sinus arrhythmia. 
The change is best observed in Lead I. There is a slightly prolonged P-R 
interval, which indicates a tendency to heart block. Both the sinus irregularity 
and the heart block are due to digitalis. 

the health of their beloved charges, we must thoroughly under¬ 
stand and be able to point out the manifestations of such 
changes. Sinus arrhythmia is nothing more or less than a 
periodic quickening and slowing of the heart rate. Normally 
in the child the heart quickens during inspiration and slows 
during expiration. As youth approaches, this variation is apt 
to be lost and by adult life it has altogether disappeared. In a 
young subject this change in heart rate may be produced by 















































30 


KEY TO THE ELECTROCARDIOGRAM 


deep inspiration and expiration. A few persons show sinus 
arrhythmia during their whole lifetime, although in the latter 
case the abnormality may be independent of respiration. 

Much has been studied and written in regard to the loss of 
balance between vagus and sympathetic control, and a certain 
school of thinkers has gone so far as to attribute a whole class 
of diseases to “vagotonics” and to look for another set of 
symptoms in “sympathicotonics”—but the subject is very far 
from being unravelled, and is further complicated by the 



Fig. 7.—Electrocardiogram, showing slight sinus arrhythmia, which is only 
observed by a careful measurement of the spaces between the beats. 


mutual relation of these plexuses with the endocrine system; 
it is an established fact, however, that the vagus nerve takes a 
much higher degree of control in some persons than in others, 
and that the functions under its domination are correspond¬ 
ingly modified. A heightened vagus control, for instance, 
tends to keep the pulse rate down in persons who show vagus 
predominance. “ Yagotonicity ”■—to borrow a phrase from some 
advanced workers—produces a slow pulse after slight exertion, 
and during the convalescence after an illness. While other 
persons, in whom another portion of the nervous system conn- 


















































































SINUS ARRHYTHMIA 


31 


terbalances, or tends to get the upper hand, show a naturally 
accelerated pulse. 

In connection with the latter manifestation, it is quite con¬ 
ceivable that in youthful subjects of a highly strung or neurotic 
type, nervous imbalance may produce an excitation of the pulse 
without any definite organic disease. The heart may be looked 
upon as “ irritable ” and likely to establish an abnormal rate, 
which will persist for a long period of time, even under ordi- 
narv conditions. The rate will be decidedlv increased under 
the stimulus of excitement, fatigue, etc. 

The important point to remember in regard to sinus arrhy¬ 
thmia is that modern cardiology has taught us to appraise it at 
its true value, and that we may safely discard it as a factor of 
clinical significance. Formerly it was supposed that this was 
a form of heart disease, necessitating a life of semi-invalidism 
for the unfortunate child in whom it was noted. The electro¬ 
cardiogram has proved a real blessing, in that it shows this 
abnormality to be so common as to be practically normal, and 
thus releases the little person who manifests it from the result 
of fears of the over anxious parents, and permits him to romp, 
play, and study his way along the normal path of development. 


CHAPTER V 


PARTIAL HEART BLOCK 

INSTANCES IN WHICH THE VENTRICLE ACTS 
ABNORMALLY AFTER THE AURICLE 

It is advisable to consider first for a moment the fact that 
impulses are carried from one part of the heart to another and 
it will be found that many heart irregularities are due to some 
defect in this conduction system. The system can be thought 
of as being composed of fibers which carry impulses. These 
impulses are first originated at what has been named the “pace¬ 
maker,” which is situated high up in the auricle and consists 
of a tiny bundle of specialized fibers. From the pace-maker 
these impulses are transmitted over a system of paths which 
run through the walls of the auricle and then they all join again 
to form a cable which traverses the partition between the 
auricle and the ventricle. This cable is known as the “bundle 
of His.” As it emerges into the ventricle the strands again 
separate into two bundle branches and then into countless 
branches which spread all over the walls of the ventricles. 

Each impulse from the pace-maker acts on the auricle, which 
in turn contracts, and then the impulse passes through the 
cable into the ventricle, which also responds by contraction. 
If the heart is normal this occurs with everv heart beat and 
carries on with monotonous regularity throughout life. 

Of course, these impulses travel very quickly and the ven¬ 
tricle will not act until it receives its impulse, which occurs at 
about one-fiftli of a second after leaving the auricle. After the 
ventricle contracts, it rests until the next impulse is received. 

The cable occasionally becomes injured or gets partly out of 
order in some other way. This occurrence causes the impulses 
coming from the auricle to have difficulty in passing through 
the injured cable, and it therefore takes a longer time than nor¬ 
mally. When the current finally reaches the ventricle, the latter 
contracts. As there is nothing the matter with the wires in the 


PARTIAL HEART BLOCK 


33 


auricle the next impulse reaches the cable in normal time, hut 
this again has difficulty in transmitting it. These impulses as a 
result often begin to pile up within the cable and some of them 
may be lost and the ventricle, therefore, beats less often than the 
auricle. This condition is called u heart block” or partial 
heart block, because the bundle is not entirely severed but still 
works imperfectly. 

What, then, will be the autograph of such a heart when seen 
in the electrocardiogram? The P wave, as has been seen, re- 





_ O . ._ 

P P P p p p p i 

mmm . . . 

T 



- .f 





... ... ... .T \' r ‘. t. r . ... i 




■ !• J ... _.J ! | -U :!• |- ! 1 |: : j 



Fig. 8. —Electrocardiogram illustrating heart block. Every other auricular 
wave is followed by a ventricular contraction. The stimulus from the 
intermediate auricular contraction is blocked. When the stimulus passes from 
the auricles to the ventricles the conduction time is 0.26 second, which is 
abnormally long. 

presents the contraction of the auricle, and the R wave 
that of the ventricle. The interval between the two is called 
the P-R interval, and normally takes about one-fifth of a second. 
This time is indicated by the vertical lines on the film. In 
heart block the P-R interval is naturally lengthened, because 
this is a record of the time it takes the impulses to pass through 
the cable which is damaged in heart block. 

Sometimes this may be the only evidence of heart block that 
can be found. Or one of the waves occasionally will fail to get 
































34 


KEY TO THE ELECTROCARDIOGRAM 


through if the condition is a little more severe and there is a 
loss of the P waves at the ventricular end of the cable. In 
more advanced conditions many waves fail to get through and so 
the auricle is found to be beating at a faster rate than the 
ventricle. These rates are often spoken of as “three-to-two 
block, ” the three representing the auricular beats and the two 
the ventricular beats; “four-to-two block,” and so forth. 

Since the P wave always means auricular contraction, more 



Fig. 9.—Electrocardiogram illustrating the earliest manifestation of heart 
block. In this record the interval from the beginning of the P-wave to the 
beginning of the ventricular wave measures 0.28 second, which is distinctly too 
long. This shows diminished function of the function of the A. V. bundle, which 
is the lowest grade of heart block. 


P waves than R waves would be expected. This fact is what 
actuallv occurs. 

Partial heart block may occur during all ages and from var¬ 
ious causes, among the most important of which are: rheumatic 
fever, syphilis, influenza, typhoid fever, occasionally diphtheria 
and other acute febrile diseases. The taking of too much 
digitalis is another very important cause of heart block. 








































PARTIAL HEART BLOCK 


35 


\\ lieu heart block occurs it is a solemn warning to stop using 
the drug immediately. 

The outcome of heart block depends, of course, upon the 
amount and character of the damage done to the cable. If 
there is a progressive lesion, such as a tumor, the condition will 
go on to a complete severence. In syphilis, the condition may 
be checked by anti-syphilitic treatment, although the strands 
already broken can never be replaced. After the acute fevers, 
excepting rheumatism, the heart usually returns to health. It 



Fig. 10.—Electrocardiogram illustrating almost complete heart block. The 
auricular waves occur regularly 75 times a minute; the ventricular waves usually 
occur regularly 38 times a minute, and without any relation to the auricular 
contractions. Some times, as seen in Lead III, the auricular contraction is 
followed by a ventricular contraction, with a P-R interval of 0.20 second. This 
shows that the Bundle of His can still function and therefore the block is not 
complete. 

is of great importance to remember that heart block resulting 
from too much digitalis may be relieved almost immediately 
by atropine. 

Before exact methods of heart records came into practical 
use partial heart block was unrecognized and thus went un¬ 
treated until the grave condition of complete heart block be¬ 
came established. How could any one tell that the auricle was 









































































36 


KEY TO THE ELECTROCARDIOGRAM 


beating faster than the ventricle excepting when the auricular 
pulsations could be occasionally counted in the neck? And, 
still earlier, where only the P-R interval was lengthened, how 
could one perceive that fact ? 

So, this is just another instance where the electrocardiogram 
makes everything very simple, for it shows that some P waves 
are found to be occurring regularly without R waves following, 
and the P-R interval is discovered to be more than the legitimate 
one-fifth of a second in length. These signs all spell HEART 
BLOCK in capital letters and the physician who knows how to 
read this language can make use of modern methods, and is 
able to put into practice methods that would fail with a more 
limited knowledge. 


CHAPTER VI 


COMPLETE HEART BLOCK 

INSTANCES IN WHICH THE AURICLE AND VENTRICLE 
ACT INDEPENDENTLY OF EACH OTHER 

The preceding chapter has described in detail what happens 
when that bundle of fibers which carries impulses responsible 
for ventricular heats following those of the auricle is damaged. 

If this bundle of fibers is completely severed a very remark¬ 
able thing occurs. It would be expected that if the ventricle 
was cut off from its dynamo it would not run, just as no explo¬ 
sion would take place in a cylinder of a gas engine if there was 
no spark. If this were true, life could last but a moment after the 
connection was broken, for that portion of the heart which sup¬ 
plies blood to the body would fail to beat. Nature has provided 
for this condition in a curious way. If the “bundle of His” is 
completely blocked, the ventricle immediately becomes its own 
dynamo and begins to beat absolutely independently of the 
auricle. 

In such a condition the ventricle will contract at a slow rate 
and directed by impulses coming from a new point of stimulus 
production in the ventricle itself. Or impulses may be only 
partially lost in the bundle and provoke the so-called “two-to- 
one block,” or three-to-one block.” 

Although one would expect that the electrocardiogram of this 
condition would be very similar to that of partial heart block, 
this is not always the case and complete heart block signs its 
name in unmistakable letters. This is explained by the fact 
that, whereas in partial heart block there are many P-R-T 
complexes, even though the P-R interval is lengthened, in 
complete heart block the P portion and the R-T portion have 
nothing to do with each other. This is, of course, due to the 
fact that the connection between the auricle and the ventricle 
is completely severed and the P current ends at the break of 
the wire. The ventricular contraction which is induced by its 


37 


38 


KEY TO THE ELECTROCARDIOGRAM 


own independent current is no longer influenced by tlie auricle 
but takes place at another time. 

The autograph would, therefore, have P waves occurring at 
regular intervals and since these normally would represent the 
normal pulse rate they probably would lie somewhere between 
70 and 90 per minute. The R-T waves are seen in fewer 
numbers than the P waves, as the independent rate of the 
ventricle is usually a slow one. Occasionally they reach an 
extremely slow rate which at times is as low as twenty per 


1 




; r : i' : f : r t i i : | . a. .. . : ! ■ i i ! : : 


Fig. 11. —Electrocardiogram illustrating complete heart block. The auricular 
waves occur regularly at a rate of 60 times a minute. The ventricular waves are 
slow and regular at 40 a minute. These ventricular waves are abnormal. (See 
Chapter on Bundle Branch Block.) 

minute. It may sometimes happen that a P wave will appear 
just before an R wave, thus giving the appearance of a normal 
P-R-T complex, but such an occurrence is only occasional and 
accidental. In the same way, if the waves happen to coincide 
the P wave may be entirely lost if consolidated in the R or T 
wave. 

Complete heart block is a serious condition, for it indicates 
that extensive damage has been done the heart. There is little 
















































COMPLETE HEART BLOCK 


39 


hope for its cure excepting when due to syphilis or overdoses 
of digitalis. Heart block should always be suspected when the 
pulse rate is below fifty and the patient should be immediately 
sent to the nearest available electrocardiograph for study. 

Adams-Stokes disease, in which there are fainting attacks, 
is evidence of complete heart block. These attacks may be due 
to insufficient blood supply to the brain from the heart which is 
beating so slowly it cannot supply the vital necessities of the 
brain. 


CHAPTER VII 


PREMATURE CONTRACTIONS 

INSTANCES IN WHICH THE AURICLE OR THE 
VENTRICLE ACTS OUT OF TIME 

Tims far, the disturbances of the heart beat which have been 
described have given normal P, R, and T waves, although the 




Fig. 12.—Record of a patient who had auricular premature beats. In Lead I 
and Lead II the premature beats of the ventricle are seen preceeded by a differ¬ 
ent shaped P-wave due to the premature auricular contraction. 


interval between these waves may have been lengthened or 
shortened. In other words, the heart muscle has been to all 
appearances, normal, and the disturbances rested with the 
conduction system. The parts of the telegraph system which 
send and receive messages may be in excellent working order 
and capable of transmitting correct messages but if the wires 
are damaged they cannot function properly. 

Let us now see what happens when the conduction system 


40 














PREMATURE CONTRACTIONS 


41 

remains intact but the heart muscle itself does not function 
correctly. In this connection the auricle should be considered 
first. Thus far, the auricle has contracted in a normal manner 
in response to stimuli received from the normal pace-maker. 
This records itself by a deflection of the string in the electro¬ 
cardiogram forming the natural P wave. As occasionally 
happens, an impulse may arise elsewhere in the auricle than at 
the pace-maker which really may be anywhere. Some point 
may become over-irritable and momentarily supersede the in- 




F-r“* 

A 



Fig. 13.— Record of a patient who had auricular premature beats. In Lead II 
the premature P-waves cannot be plainly seen, but in Lead I and III, they can 
be made out, falling on the top of the T-wave preceeding. 


fluence of the pace-maker and thus set the pace from there. 
When this happens a distorted P wave is found instead of a 
normal one. Such an impulse travels down as well as up 
through the auricle to the connecting bundle and finally sets 
off the ventricle. The ventricle, being undamaged, cares little 
where the impulse came from and does its duty by contracting. 

It is as if some one tapped in on a telegraph wire and sent a 
message. The recording instrument at the other end responds 
with its usual clicks and does not distinguish whence the mes- 













42 


KEY TO THE ELECTROCARDIOGRAM 


sage came. The R-T or ventricular complex will thus be a 
normal one. 

We, therefore, distinguish between what are known as “pre¬ 
mature contractions” of the auricle and normal ones. They are 
called “premature” because they come between two normal 
beats and therefore appear before the second normal beat. In 
order to illustrate this point further, consider that the heart is 
beating at a normal rate of about eighty per minute. Each 
P-R-T complex will be equally spaced from every other and 



Fig. 14.—Ventricular premature beats X coming from the right ventricle. 
Notice how these waves differ from the usual waves of the electrocardiogram. 


all will have a perfectly similar shape. A queer looking complex 
is suddenly thrown in and on examination it is found there is 
nothing wrong with the R-T part of the complex but the P 
wave is either upside down or taller or perhaps wider than the 
other P w T aves. This finding spells “auricular contractions,” 
otherwise known as “auricular extrasystoles.” (Fig. 13) 

If the irritation which causes these premature contractions 
is of longer duration there may be two or three more extra¬ 
systoles following each other in sequence and then returning 
to normal rhythm. It must be remembered that while these 



















































PREMATURE CONTRACTIONS 


43 


contractions are going forward, normal impulses are coming 
from the pace-maker. These, being absorbed in the abnormal 
complexes, however, become lost. 

The ventricle may beat out of time in the same manner as 
the auricle. In this case there is nothing the matter with the 
auricle. There has been, however, a point of irritation set up 
somewhere in the ventricular wall which has started indepen¬ 
dent contractions, and since these have not occurred through 


•••• 



Fig. 15. —Record of a patient avIio had bigeminal rhythm X due to ventricular 
premature beats from the right ventricle. In Lead I, two ventricular premature 
beats occur together. This is sometimes a digitalis effect. 


normal paths, their records will be abnormal. Such a record 
will consist of badly distorted R-T waves, the amount of distor¬ 
tion depending on how far the point of irritation lies from the 
normal pathway. These deformities may be extreme and may 
dip down below the line to a considerable extent or they may go 
hififli above the line. Sometimes they are both above and below 
the line in the electrocardiogram. 






























































































44 


KEY TO THE ELECTROCARDIOGRAM 


In ventricular extrasystoles one usually lias to deal with a 
decided disturbance in rhythm due to what is known as 
the “compensatory pause.” The meaning of this term is simply 
that when the ventricle is stimulated during contraction it will 
not respond to the stimulus so it waits for the next stimulus 
from the auricle. 

Picture again a regular heart rate with normal evenly spaced 
and similarly shaped P-R-T complexes. A bizarre shaped wave 
is suddenly found to be thrown in. On measuring the width 



Fig. 16.—Another instance of premature ventricular beats (X). These have 
very large waves clue to beats from the right ventricle. 

of this wave it is discovered that it is equal to that of any 
normal preceding R-T complex, indicating that it comes from 
the ventricle. Meanwhile, normal P waves are occurring and 
when one of these falls on such an abnormal complex it finds 
that the ventricle has already contracted and is therefore un¬ 
able to respond. There is then a pause where nothing happens 
until the next P wave occurs. This is the ‘ ‘ compensatory pause ’ 1 
mentioned above. 

There may be several ventricular contractions following each 
other just as there may be many auricular contractions in 











































































































































































































































PREMATURE CONTRACTIONS 


45 


auricular extrasystoles. There is a series of weird waves of 
various shapes here also, but whereas in the first instance they 
were followed by normal R-T complexes, in this case they 
consist of abnormal R-T complexes. 

A\ hen ventricular extrasystoles occur in series they do so 
rhythmically, that is, there may be two of them followed by two 
more, then two more and so on. This is called “coupling” and 
gives rise to the well known term “pulsus bigeminus.” If the 
extrasystoles occur in threes the condition is called “tripling” 
and is spoken of as “pulsus trigeminus” and so on. It is well 



Fig. 17.—Record of a patient who had only occasional ventricular premature 
beats (X). Note how much these waves are in contrast to the waves of the 
ordinary beats. 


to remember that such series are one of the first indications of 
over-doses of digitalis. 

Of course, there may be many variations in extrasystoles. 
For example, there may be both auricular and ventricular extra¬ 
systoles, both starting from different foci, thus giving a series 
of variously shaped waves, or again there may even be extra- 
systoles beginning in the connecting bundle between the auricle 
and the ventricle. Although these may for the moment com- 



























46 


KEY TO THE ELECTROCARDIOGRAM 


plicate the picture, they can be readily understood by a brief 
study of the electrocardiograms. 

With the exception of sinus arrhythmia, auricular and ven¬ 
tricular extrasystoles are the most frequent forms of irregu¬ 
larities of the heart beat. They are most often found in cases 
of long standing myocarditis, although they may occur at any 
age indicating a temporary derangement of the heart function. 
Their presence need be no cause for alarm as they, themselves, 
rarely embarrass, but they should be considered as indications 
of underlying cardiac damage. 


CHAPTER VIII 


SIMPLE PAROXYSMAL TACHYCARDIA 


In order to appreciate the term, paroxysmal tachycardia, one 
must recall the fact that the vagus nerve acts as a brake on the 
heart. The heart will slow down markedly if this nerve is 
stimulated as, for instance, by pressing along the side of the 



Fig. 18.—Eecord of simple paroxysmal tachycardia. The auricles beat at 140 

a minute, and each auricular contraction is followed by a contraction of the 
ventricles so that the heart is regular. This record also indicates right ventricular 
preponderance. 


neck. One releases the vagus nerve in this same manner by 
means of atropine which paralyses its endings. The heart will 
then tend to run away. 

Every one is familiar with the clinical condition known as 
paroxysmal tachycardia in which the rate of the heart is exces¬ 
sively fast. There are many evidences to show that this con- 


47 




































































































































































































































































































































































48 


KEY TO THE ELECTROCARDIOGRAM 


dition is due to loss of control by the vagus nerve, thus allowing 
the heart to have its own way. One of these evidences is that 
pressure on the neck over the vagus nerve may frequently bring 
it under control. 

It was the electrocardiogram which taught the mechanism of 
this disturbance. The statement has frequently been repeated 
that a normal heart beat gives a complex of three waves, P, R, 
and T, which although they may vary individually are never¬ 
theless recognizable as normal curves. If it were assumed that 
the heart were beating regularly at a rate of about eighty per 



i i 


i i i 


P 


i pi p s P, 





Fig. 19.—Record of simple paroxysmal tachycardia in which the auricles beat 
at 160 a minute, the ventricles follow regularly after the auricles. 


minute, thus recording a normal autograph on the film, and if 
the rate were suddenly doubled or more than doubled it would 
indicate that a so-called paroxysm had set in. If the P-R-T 
complexes which now appear are examined, the R-T part of the 
complex is found to be identical with those recorded when the 
heart was beating normally. Since it is a known fact that the 
R-T wave spells the action of the ventricle it can be assumed 
that there is nothing wrong with this portion of the heart. 

The P waves should next be examined and they will be found 
































SIMPLE PAROXYSMAL TACHYCARDIA 


49 



Fig. 20.—Record of a very rapid paroxysmal tachycardia. The auricular beat 
here is 200 a minute and the ventricles follow regularly after each auricular beat. 
The record also indicates left ventricle preponderance. 


R 

' * ! i ! ! I P‘ P PI p P p I ! ! i ! j i t 

v* ** v* >■ v* ** v* yg y*v* w* In yi ym y* \/i fcijfWy* w @ '**v*w« 



• 





— 



- 

t - 





; t. 

-. 



•— j--- 

r _. .. 

— 




P 


— 













' 

:: . - 

L: _ 

U- 



— 


i 

U -.1 






~ - 

• 



Fig. 21.—Record of an extremely rapid paroxysmal tachycardia, the auricular 
beat being 240 a minute. The ventricles follow regularly after each auricular 
beat. 







































































































































50 


KEY TO THE ELECTROCARDIOGRAM 


to be entirely different from those which appeared before. 
They may be higher, of a different shape, inverted, or perhaps 
diphasic, that is, partly above and partly below the line but 
they certainly will be different. 

The question is: What is the explanation for this condition? 
It simply means that there is a disturbance of the auricle and 
that instead of the impulses arising at the pace-maker, which 
always gives normal P waves, the auricle at some point has 
set up a new pace-maker which has over-ruled the normal one. 
The P wave from the new place has a different shape. 


B 



Fig. 22.—In this record Lead III illustrates a short paroxysm of ventricular 
premature beats (X) which constitutes a short paroxysm of ventricular 
tachycardia. The rate is about 175 while it lasts. 


This picture of the activity of the auricle recalls at once 

that of auricular extrasystoles. To be sure, it is a matter of fine 

distinction as to whether or not paroxysmal tachycardia may 

be considered as a long chain of equally spaced auricular extra- 

svstoles. This point is all the more suggestive when it is 

remembered that extrasystoles sometimes may occur in twos, 

threes, fours, fives, and so on, and in these instances the series 

may be extended into the thousands. 

«/ 






















SIMPLE PAROXYSMAL TACHYCARDIA 


51 


11] is amazing condition is usually found in young adults who 
may or may not have had previous heart trouble. Once heart 
trouble occurs in an individual, he is predisposed to other 
attacks. The attacks may last for a moment or may continue 
over a period of several days. If the latter, the heart may be 
considerably embarrassed. The presence of paroxysmal tachy¬ 
cardia should always lead one to look elsewhere for heart 
damage. 


«• * 
•« 
4 * 


• ••• 
* 

• •• 


• • 
• • • 
• » 
• • 





"~A » 



Fig. 23.—Record of a typical paroxysm of ventricular tachycardia. The 
ventricles beat 180 times a minute, quite regularly. 


It is well to remember that although these attacks usually 
stop of their own accord quite as suddenly as they began, 
nevertheless pressure over the vagus nerve on either side of 
the neck, strong pressure upon the eyeball, or leaning far 
forward, may stop the attack immediately. 

The electrocardiograph is the only instrument whereby one 
can distinguish between a normal over-acting heart, paroxysmal 
tachycardia, and auricular flutter which is fully described in 
the following chapter. 















































































































































































CHAPTER IX 


AURICULAR FLUTTER 

INSTANCES OF VERY RAPID ACTION OF THE AURICLE 

All cases of extremely rapid heart action were classed as 
paroxysmal tachycardia until the accurate instruments which 
portray the action of the heart were perfected. It has been 
only recently that the electrocardiogram has revealed a con¬ 
dition which, although similar to paroxysmal tachycardia in 
its general picture, is quite different in its mechanism. This 
condition is called auricular flutter. It is important that it 
should be so recognized because it usually implies a greater 
degree of damage to the heart than that found in paroxysmal 
tachycardia. 

The question is, why is this condition called auricular flutter ? 
To begin with, as in paroxysmal tachycardia, the vagus nerve 
is apparently out of action and impulses are sent down through 
the heart at a tremendous rate of speed, sometimes 300 or more 
per minute. These impulses are transmitted as usual through 
the auricle and then through the connecting bundle to the 
ventricle which, in turn, responds by contraction. The ven¬ 
tricle, however, since it does most of the work of the heart by 
sending the blood into the circulation, requires more time for 
rest than the auricle. It cannot keep up with such an exceed¬ 
ingly fast pace. The result is that after the ventricle has 
contracted in response to one of these stimuli the next one, two. 
or three may find it either still contracting from the last stimu¬ 
lus or taking its needed rest, and therefore they have no affect 
on the ventricle. 

The very rapid rate observed in paroxysmal tachycardia is 
not the only finding one discovers in looking at the electro¬ 
cardiogram of this type. A great many P-R-T complexes will be 
found, but between each one of these there will be one or 
more isolated P waves. These are records of the contraction of 
the auricle to which the ventricle could not respond. 


52 


AURICULAR FLUTTER 


53 


In the heart of a dog in which auricular flutter has been 
produced experimentally one will find the auricles to be beating 
so tast that they are in a continual state of flutter and hence 
the term, “auricular flutter.” 

Auricular flutter resembles heart block but in this instance 
there is no damage to the cable connecting the auricle 
and ventricle but in the ventricle itself, which refuses to work 
at any such exorbitant speed as the new pace-maker demands. 
Therefore, as in heart block, there is a two-to-one, tliree-to-one, 



Fig. 24.— Record which illustrates auricular flutter. The auricles are beating 
330 times a minute, quite regularly; the ventricles are beating at exactly half 
this rate. Flutter waves are marked F. F. 


or two-to-tliree block, depending on the proportion of auricular 
to ventricular beats. 

The electrocardiogram has given physicians an insight not 
only into the presence of this condition, but also as to wliat 
takes place as it disappears. Instead of the heart at once 
resuming a normal rate, as in paroxysmal tachycardia, the 
excess of P waves disappears first, leaving a condition of 
paroxysmal tachycardia. A state of auricular fibrillation which 
will be described later is now assumed. In the end the normal 
rate is resumed. 












































































































54 


KEY TO THE ELECTROCARDIOGRAM 


Although paroxysmal tachycardia is a matter of days in 
duration, auricular flutter lasts longer and sometimes stretches 
over a period of months or years. Digitalis is extremely valu¬ 
able in relieving auricular flutter. 

The study of auricular flutter is still too new for anyone to 
be able to differentiate it from paroxysmal tachycardia in so 
far as its cause is concerned. It is known, however, that it 
gives the highest pulse rates and that it has a different method 



of offset and probably of onset from paroxysmal tachycardia. 
It occurs in the same type of individual. 

Recent study on auricular flutter which is being carried on 
entirely by the aid of the electrocardiograph promises some 
very interesting facts in the near future. 















































































































































































CHAPTER X 


AURICULAR FIBRILLATION 

INSTANCES OF TREMBLING PARALYSIS OF THE AURICLE 


Tlie condition of trembling paralysis of the auricle is clini¬ 
cally known as auricular fibrillation. This remarkable condition 
seems hardly compatible with life and yet people may have it 



Fig. 26. —Record illustrating auricular fibrillation. The small waves marked 
f,f are due to fibrillation of the auricles. The ventricular waves are seen to 
be irregular and rapid. They occur 130 times a minute. 


continuously for decades. In this state the auricle has lost 
all semblance of orderliness, the influence of the pace-maker 
is gone, and even various abnormal contractions of the auricle 
heretofore described, are no longer recognized. In their place 
there has been set up a tremor which comprises countless 
fibrillary twitchings, and even these are not orderly. They 
arise apparently from myriads of foci throughout the auricular 


55 
































































































































56 


KEY TO THE ELECTROCARDIOGRAM 


tissue. The record of these twitchings reminds one of the 
tracings of a seismograph, which records the tremblings of 
distant earthquakes. 

AVliat type of a picture, then, can one expect from such a 
disturbance? Instead of a normal or even abnormal P wave, 
as found heretofore in other auricular contractions, there are 
no P waves at all, but merely countless little tremulous lines, 
each of which is a record of a tremor. There is nothing the 
matter with the conduction of each of the impulses down toward 
the ventricle and as a result they all crowd upon the connecting 


1 




!TTT~T 


Fig. 27. —Record of another patient, which illustrates auricular fibrillation. 
The f,f waves are seen running throughout the record. The ventricles here 
are very irregular. There is a ventricular premature beat in Lead II. 


bundle, each one eager to get through. It has been estimated 
that there are five-hundred or more of these each minute, or 
about W every second. Since there is no disturbance of the 
ventricle, it does its best to oblige, but just as in auricular 
flutter, it cannot keep up such a pace. Since these twitchings 
represent impulses of different strengths, the ventricle receives 
correspondingly varied stimuli. Its response to these is, there¬ 
fore, varied as to both size and frequency. For example, a 
strong stimulus will incite it to give a strong beat. A half 



























AURICULAE FIBRILLATION 


57 


a dozen or more stimuli falling upon the ventricle find it refrac¬ 
tory while it is beating. Once it has recovered and rested 
from this beat the next stimulus to which it can react may be 
very weak, so that the ventricle will give a small beat. This 
popular explanation conflicts with the theory of total response. 
But if this little book proves a key to the subject the reader 
will be in a position to follow it into more technical literature. 

The electrocardiogram of auricular fibrillation will show at 
the beginning a total absence of P waves for which the tremors, 
described above, are substituted. R-T waves of widely varying 




I bJL f f R f T ff f f T f f f. 

/*VW\A’ * 


; i T~T f 


.1 i 


Fig. 28.—In this record the waves due to auricular fibrillation (f,f,f) are very 

plain and there is a slower ventricular rate. 


size occur and in absolutely irregular rhythm. Since the ven¬ 
tricle is not altered they are similar in shape. Although it is 
sometimes very difficult to distinguish this condition clinically 
from frequent extrasystoles, it can be diagnosed at a glance 
in the electrocardiogram. Auricular fibrillation occurs chiefly 
in damaged hearts. Ventricular extrasystoles may occur with 
it, though never auricular extrasystoles. This condition is 
recognized by the entirely different shape of the R-T waves. 

Fibrillation is considered bv many as evidence of a myocar- 
















































58 


KEY TO THE ELECTROCARDIOGRAM 


ditis. Sometimes it may be transient, as after extreme exercise 
of a damaged heart or during pneumonia. The tendency to it 
usually remains after it has once set in. 

Digitalis is more valuable in this heart condition than in 
any other. One can attempt to block as many impulses of the 
heart as possible at the connecting bundle with digitalis. Thus, 
the ventricle is spared excessive stimulation. Since it is known 
that digitalis must not be given as a rule in cases of frequent 



Fig. 29. —Record of a patient who had auricular fibrillation. The fibrillation 
waves (f,f,f) are plainly seen where they are marked and at many other places 
in the record. The right ventricular preponderance is shown by the large size 
of the S waves in Lead I. 


extrasystoles it is extremely important that one should differen¬ 
tiate between these two conditions. It is in this connection 
that the electrocardiogram gives a clear vision as to our course, 
rather than to leave it to hazardous chance. 















































































CHAPTER XI 


ALTERNATION OF THE PULSE 

This condition is otherwise spoken of as Pulsus Alternans. 
Although it is a very serious disturbance it has been extremely 
rare in my own experience. It is manifested by large and by 
small beats of the heart regularly alternating with each other. 
It is usually discovered in the blood pressure examination by 
auscultatory methods. At a certain level of pressure every 
alternate beat only is heard. Occasionally it is said to be 
observed in electrocardiograms. I have no example of it in my 
own collection. It is said that the P, R, T, waves look all alike 
except for the height of the alternating R, T waves. My own 
belief is that the phenomenon has a good deal to do with the 
tonicity of the peripheral blood vessels, rather than with the 
heart beat itself. This would explain the absence of evidence 
by the electrocardiogram. There are certain electrocardiograms 
in which there seems to be lengthening of the R and T waves, 
but they must be of a different type, as they do not correspond 
clinically with the pulsus alternans cases, which, in our experi¬ 
ence, have always been observed in exhausted hearts. From 
a clinical standpoint, pulsus alternans runs only Avith se\ r erely 
damaged hearts. 

Paul White, in his study of this condition, says: “In regard 
to a definition of the term, pulsus alternans is used to indicate 
alternating beats which are unequal in force and volume. The 
inequality is due to the unequal development of pressure in 
the left ventricle. The inequality of the beats at the radial 
artery is appreciated at times by palpation alone. It may also 
be detected on taking of blood pressure at the brachial artery. 
A graphic tracing of the radial artery shows the condition 
best. The electrocardiogram does not show pulsus alternans, 
even when it is distinct in the mechanical tracing. There is a 
type, however, which can be detected electrically. When the 
R wave or the T wave is tall, the mechanical Avave is short, or 
the condition m&y be reversed. In the mechanical type there 


59 


60 


KEY TO THE ELECTROCARDIOGRAM 


is not alteration of rhythm, and the distance between the beats 
is regular. Pulsus alternans usually arises from the left ven¬ 
tricle, but it can also have origin in the right ventricle or the 
auricles. 

“Two explanations have been advanced as to the cause of 
this irregularity: (1) It is supposed that the muscle fibers of 
the ventricle are not capable of contracting with equal force at 
each systole; some portion failing at alternate cycles; perhaps 
some portion or another of the muscle is defective. (2) Another 
view is that the heart, as a whole, is defective in contractile 
power and defective fibers are widely distributed. If the first 
explanation is true there ought to be more electrocardiographic 
evidence. Statistics show that the age incidence is less in 
persons under forty (15 per cent, of cases); and more common 
over 50 (62 per cent, of cases). In cases examined with regard 
to hypertension, it was found in 51 per cent, of hypertension 
patients. It is also found in association with acute infectious 
disease. The prognosis is serious. The treatment is that of 
the underlying condition.” 

A. E. Cohen is in agreement with Paul White as to the 
comparative frequency of this finding. 

An explanation of the relative infrequency of pulsus alternans 
in my experience, as compared with that of other writers, 
Cohen and Paul White, for example, is that they quote statistics 
from hospitals where the staff is constantly on the watch 
for such phenomena, and the internes have the patients under 
constant observation, bearing this condition in mind. They 
may find alternation as an occasional incident, and report the 
whole case as one of pulsus alternans. A gentleman, who 
consulted me, and who arrived after a long motor ride, and who 
had suffered myocardial damage, showed a picture of bundle- 
brancli-block in his electrocardiogram, but might not have 
shown alternation under other circumstances, when not under 
strain of fatigue. The classification of cardiac irregularities 
under the tutelage of Lewis, into seven varieties, includes pulsus 
alternans. In my own teaching, I have found it burdensome 
to carry this seventh type, because of its very limited applica¬ 
tion in my own experience. This is one reason why I should 
like to see the question opened up to have a consensus of 


ALTERNATION OF THE PULSE 


61 


opinion on the importance of this phenomenon, and whether it 
is worth while to carry it still as one-seventh of the classification. 

Perhaps the time has come for a new classification. In the 
present state of dissemination of knowledge of the electrocardio¬ 
graph by the profession, it would seem to me good policy not 
to vary our teaching until we know a good deal more about it. 


CHAPTER XII 


THE EFFECT OF VALVULAR DISEASE ON THE HEART AS 
SHOWN BY THE ELECTROCARDIOGRAM 

Thus far both normal and abnormal contractions of the auricle 
in response to stimuli which travel through their walls have 
been spoken of. These contractions have given us such distinct 
curves they could readily be recognized. The heart valves, 
which are but reflections of the thin inner wall of the heart, 
have no muscular tissue in them and therefore set up no waves 
of their own. It can only be said that the electrocardiogram 
is helpful in valvular disease of the heart because of the secon¬ 
dary changes which occur in the heart muscle. Such electro¬ 
cardiograms are indeed very useful. Since they are secondary 
evidence, however, one must not ask too much of them but 
merely take these electrocardiograms of valvular disease for 
what they are worth, which after all amounts to a great deal. 

Mitral Stenosis. In mitral stenosis it can be truly said that 
the electrocardiograms are frequently diagnostic of the disease. 
Since the left auricle must contract powerfully to send the blood 
through the small stenosed mitral valve, the P wave which 
represents the auricle may be much exaggerated. It may be 
several times higher than normal, or perhaps broader and some¬ 
times notched, or again it may have a flattened plateau-like top. 
In most cases of mitral stenosis of long duration there is a 
preponderant enlargement of the right side of the heart. All 
these indications appear in the electrocardiographic picture. 
In the first lead instead of an upright R wave there is an 
inverted peak and an exaggerated P wave followed by R waves 
indicating right sided preponderance, strongly suggestive if not 
diagnostic of mitral stenosis. Many cases of mitral stenosis 
are associated with auricular fibrillation. In these instances the 
exaggerated P waves are replaced by exceptionally large oscil¬ 
lations. Oscillations of great amplitude are seen only in mitral 
stenosis. 


62 


THE EFFECT OF VALVULAR DISEASE ON THE HEART 


63 


Aortic Disease. In aortic disease the electrocardiograms give 
no constant curves. The auricles, being usually unaffected, 
inscribe normal P waves. Both the right and the left ventricles 
are usually thickened but, since the left side nearly always 
predominates, an upright R wave is chiefly found in the first 
lead, and an inverted peak in the third lead. It is interesting 
to note in this connection that a large excursion of the R wave 
and a small or inverted T wave in Lead II are quite frequent. 

Mitral Regurgitation. Mitral regurgitation gives no charac¬ 
teristic curves in the electrocardiogram. 

Pulmonary Stenosis. Pulmonary stenosis may be mentioned 
in connection with mitral regurgitation. There is always a 
right sided predominence in pulmonary stenosis and very often 
enormous amplitudes of excursion to the R wave are shown in 
the electrocardiogram. 

Congenital Defect. The diagnosis of congenital defect is 
almost certain when the R wave is found to be many times its 
normal height and is so placed as to indicate right sided 
predominance. 

Dextrocardia. Dextrocardia is another cogenital defect that 
must be mentioned. In this condition the heart, as well as other 
viscera, is transposed to the opposite side. Here, the heart may 
be working perfectly normally and so give no evidence of either 
auricular or ventricular disturbance but the electrical currents 
will be reversed and as a result Lead I will often be normal 
excepting that it will be invariably inverted. Clinically it may 
often be difficult to distinguish dextrocardia from cases in which 
the heart has been mechanically pushed or pulled over to the 
right side, but electrically the diagnosis can readily be 
made because when the heart is pushed or pulled over to the 
right the electrocardiograms show normal leads. 

O o 


CHAPTER XIII 


LESIONS IN THE RIGHT BUNDLE BRANCH 

The most striking example of definite, demonstrable, scientific 
value, when we have excepted the recognition of the six cardiac 
irregularities, is found in those people who have suffered a defi¬ 
nite, localized damage to one of the branches of the bundle of 
His. This very often is the direct result of rupture, thrombosis, 
or embolism of a vessel of the heart, the occurrence of which 
is frequently revealed in the history of the person by the story 
of an attack characterized by severe cardiac pain of long dura¬ 
tion, with very marked heart failure from which the person 
gradually recovered. As in the corresponding cerebral event, 
the lesion may be, and often is, thrombosis, sometimes it is an 
embolism, and occasionally a rupture. 

The relative frequency of this condition, in that group of 
people whose cardiac condition is of sufficient importance for 
them to seek a complete technical examination, is about 3 per 
cent., thus showing that cardiac disease is usually allowed to 
advance to a high degree of development before people receive 
the benefit of a close analvsis of their heart condition. 

4 */ 

In a group of 20 people who were suffering from this disease 
which involved the terminal branches of the bundle of His, all 
but three were over fifty years of age, and all but four were 
males. The duration of the disease previous to the time when 
the patient came to my office, was nearly always considerable. 
In only four patients was it less than a year. 

The prominent symptoms of which these people complained 
were precordial pain, dyspnea, and palpitation. Pain of some 
sort was present in all but two of these cases and was sharp and 
severe in eleven. Sometimes it was described as a sense of 
soreness or a dull pain or a feeling of oppression. The situation 
of the pain was variable, but nearly always included the precor- 
dium, at least in part. In five of the patients the first symptom 
of disease was pain, while in four the first symptom was short¬ 
ness of breath. In the remainder of this group the sypmtoms 


64 


LESIONS IN THE EIGHT BUNDLE BRANCH 


65 


had rather an insidious onset, and it was difficult for the 
patients to say of what they first complained. 

Although dyspnea is usually a prominent symptom, there 
was one of these people in whom it was not present and another 
in whom it was noticed only at night when it came on in attacks. 

Palpitation appears in attacks on exertion. It was present 
in eight of these persons. When present it is usually a dis¬ 
tressing and prominent symptom. 

Edema, strangely enough for a condition which is usually 
considered as serious, did not occur very frequently, and when 


R R 



Fig. 30. —This illustrates the waves due to intraventricular block with blocking 
of the right bundle branch. The notching of the R waves in Lead I and of the 
S waves in Lead III is very plain; also the width of these waves. 


present was not marked, except in one person. Fifteen of these 
people did not show it. 

The weakness of the heart tends to cause a congestion of the 
lungs which is manifested in cough and this was present in 
about half of these people. It was not severe, but was very 
persisent. 

When these people were examined, the most evident thing 
about them was their age. In going over their records, it is 
also evident that the majority of them had increased blood 












































































66 


KEY TO THE ELECTROCARDIOGRAM 


pressure, although it it true that some did not show this. 
Blood pressures in this series were observed as high as 220 mm 
for the systolic, and 12 of these people gave figures for the 
systolic which might be considered above normal. 

The heart rate was usually not rapid when they came for 
examination, being over 90 in only six patients, and in only one 
person was it very rapid, being 120 in that case. 

The electrocardiographic record shows the changes which 
are considered as typical of an obstruction in one of the 



Fig. 31.—Another record to illustrate intraventricular block with a right 
bundle branch lesion. In this record the notching is not so plain, but neverthe¬ 
less can be made out. The width of the abnormal waves, the R. and S. waves 
is plain enough. 


branches of the bundle of His, in all of these people. The ven¬ 
tricular waves have the large notched Q, R, S group with in¬ 
creased width and the large T wave in the opposite direction, 
which is typical. All but three of them have the Q, R, S, de¬ 
flection, chiefly upward in Lead I, and downward in Lead III, 
so that the lesion may be said to be in the right branch of the 
bundle. The other three records probably indicate a lesion in 

















































































































































































LESIONS IN THE EIGHT BUNDLE BRANCH 


67 


the left branch of the bundle. One of the records shows the 
pei son had auricular fibrillation, but in all the others the nor¬ 
mal rhythm is in force. Three cases show premature ventric¬ 
ular beats and one shows a prolonged conduction time between 
the auricles and ventricles—an example of partial heart block. 

The rr-ray pictures which were taken of these people by the 
teleoroentgenographic method show that four of them did not 
have an enlarged heart. Five of them had extremely large 
hearts and in the remainder there was a moderate enlargement. 





Fig. 32.—A record of a patient with auricular fibrillation as well as intraven¬ 
tricular block of the right bundle branch type. The R and S waves are unusually 
wide but the notching is not very plain. The fibrillation waves are indicated 
by f,f,f. 


It is a very interesting finding that eleven of these patients 
were considered to have normal valves and in four of them both 
the aortic and mitral valves were diseased, while in the 
remainder only one valve was affected. Eight people showed 
systolic murmurs at the apex which were not considered to in¬ 
dicate valvular disease. 

In our attempts to treat these people, we have been able to 
observe the response to digitalis in 16 of the 20 persons and 
have found that in seven of them it had an extremely beneficial 















68 


KEY TO THE ELECTROCARDIOGRAM 


effect. Four were only moderately benefited by digitalis and 
in five the response was poor. 

It has been said that all of these people are persons who 
are well advanced in years and so it is not surprising that our 
clinical diagnosis, after having reviewed all of the findings, 
should be arteriosclerosis in eight, cardiosclerosis in one other, 
and angina pectoris in still another. This indicates that these 
people were suffering chiefly from a condition which goes with 
age and is not especially brought on by any acute disease. 



Fig. 33.—A record that shows intraventricular block by the width of the R 
waves, but is not typical of either right or left bundle branch lesion. 


Five of them were classified under the diagnosis of myo¬ 
cardial degeneration, while four were believed to have primary 
valvular disease. In the one remaining person, our diagnosis 
was cardiac dilatation. 

Several of these people, and curiously not those who showed 
the most striking electrocardiographic pictures, were able to 
pursue their vocations in a manner equal to the average of 
their age. 

All these observations were made in private practice, and 
bear out the belief expressed by at least one of the greatest 


















LESIONS IN THE EIGHT BUNDLE BRANCH 


69 


heart specialists in the world, that the most fruitful field for 
the study of cardiology is found in private practice. 

The general condition of the heart must be very good indeed 
when it can survive and make so good a comparative recovery 
from a definite circulatory accident. It it analogous to the ex¬ 
perience that slight attacks of hemiplegia are much better 
borne and more frequently recovered from among well-cared 
for people than among a group ordinarily observed in hospital 
practice. 




T 


v r : r ■ . » : t r — rrt". .r- . ..1 r trr r- l r - : r— r -j- — r i ts -.- i 

Fig. 34. — A record which shows intraventricular block by the width of the R 
waves. The notching is not plain. The large S wave in Lead I indicates a left 
bundle branch lesion. 

The most interesting conclusion to be drawn is that acciden¬ 
tal interference with the circulatory system of the heart is 
probably very frequent and is not confined to those showing 
striking clinical manifestations. It is possible that future studies 
may reveal some means of recognizing such an accident to other 
parts of the heart muscle. There is certainly much to learn 
from the study of such groups as these. 

I happened to be looking over Wiggers’ wonderful book on 
















































70 


KEY TO THE ELECTROCARDIOGRAM 


“Circulation in Health and Disease/’ one day and I ran across 
an illustration of experimental bundle branch lesion. It struck 
me very forcibly because only two or three days previously a 
woman who had been under observation a long time for right 
bundle-branch lesion, came into the office during an attack of 
tachycardia, and her electrocardiogram was so exactly like that 
of the dog, that it struck me as a striking illustration of the 
class relationship of clinical medicine and laboratory experi¬ 
mentation in cardiology. 


CHAPTER XIV 


THE ELECTROCARDIOGRAM AS SHOWING RELATIVE 
ACTIVITY BETWEEN THE RIGHT AND LEFT 
SIDES OF THE HEART 

It is a matter of common knowledge that in many afflictions 
of the heart the ventricles increase in size. Although it is true 
that the right and left sides share in this enlargement in some 
conditions, yet, for example in mitral stenosis, the right ven¬ 
tricle will be disproportionately thickened; whereas in others, 
such as aortic disease of long standing, or a chronic nephritis 
with high blood pressure, it is the left side that enlarges the 
most. It must be remembered, however, that in such conditions 
both sides of the heart increase in size, although usually to a 
greater extent in one than in the other. 

It has become known that the R-T wave represents the activ¬ 
ity of the ventricle, and it can as a result be assumed that if the 
ventricle is abnormal in size there will be some change in this 
complex, and this is what actually occurs. 

Thus far, little attention lias been paid to the three leads, for 
the disturbances studied in the previous chapters show essen¬ 
tially the same things in all three leads excepting that one may 
be more distinct than the other. In enlargements of the ven¬ 
tricle one can distinguish between the right and left predomin- 
ences by a comparison of the various leads. 

When the left side of the heart is proportionately increased 
in size the R wave in the first lead will be steeple-like in shape 
and it is apt to reach considerable height. In the third lead, 
however, the steeple, though just as tall, is found to be in¬ 
verted below the line. 

The opposite holds true for right sided preponderance, for 
here, in the first lead the steeple is inverted, whereas it is up¬ 
right in the third lead. It is the size of these waves in Lead I 
and Lead III that indicates the proportion of predominance. 


71 


KEY TO THE ELECTROCARDIOGRAM 


72 


Clinical observation lias shown that a large number of other¬ 
wise apparently healthy people complaining of some abnormal 
consciousness of their heart action have shown a relative right 
predominance and we have taken this to indicate that there was 
in fact some abnormality of the heart even if it was not always 
easy to classify. I do not feel, with some clinicians, that be- 



Fig. 35.—A drawing to illustrate the effect of hypertrophy of the right ven¬ 
tricle and of the left ventricle upon the electrocardiogram. R illustrates the 
effect of hypertrophy of the right ventricle. The electrocardiograph picture 
in the three leads indicates right ventricular preponderance. L illustrates the 
effect of hypertrophy of the left ventricle. Right ventricular preponderance is 
shown by the small R and large S in Lead I. Left ventricular preponderance 
by the small R and large S in Lead III. 


cause preponderance may be due in many instances to certain 
chance relationship, as to position, it can be overlooked when we 
are seeking for heart disorders. The point is to give the sign 
its proper weight. 

One point that may be a clinical stumbling block in the 
matter of judging between right and left preponderance, is that 






ACTIVITY BETWEEN BIGHT AND LEFT SIDE OF HEAKT 73 

when the heart as a whole is dislocated, the observations are 
invalidated, and it is a matter for careful clinical judgment as 
to how far the observations must be discounted by our consid¬ 
eration of the amount of deformity of the heart. This difficulty 
might be met if we could in some way make our Leads corres¬ 
pond to the deformity of the heart as shown in the #-ray pic¬ 
ture. In forming a diagnosis of preponderance the position of 
the heart must be taken into consideration. 



Fig. 36.—Electrocardiogram of patient to illustrate rjght ventricular prepon¬ 
derance. The small R and large S in Lead I is the determining sign. 


In the early days of the electrocardiogram there was consid¬ 
erable question as to whether these curves gave a true picture 
of the heart enlargements. Sometimes percussion revealed a 
left-sided hypertrophy whereas the electrocardiogram indicated 
a right-sided one. Eventually it was found on post mortem 
examination that the exact science was the correct one and the 
clinician was wrong. 

At times unsuspected conditions may be diagnosed by this 
method. For instance, a preponderant right heart will lead one 
to look for other evidences of mitral stenosis in which it is well 







































































































74 


KEY TO THE ELECTROCARDIOGRAM 


known that the classical presystolic murmur may not appear 
early. Or again, a heart may enlarge considerably in the 
anteroposterior direction without any enlargement being de¬ 
tected to the left. The electrocardiogram will at once solve 
this difficulty. 



Fig. 37. —Electrocardiogram to illustrate left ventricular preponderance. The 
small R and large S in Lead III is a distinctive feature. 


One feels justified in again emphasizing that, acute as our 
perceptions may be, one cannot hope to compete in exactness 
with such physical forces as the electrical reactions. Wisdom 
may be employed, however, in subjecting these exact methods 
to our control. 



























































































































































































































CHAPTER XV 


PRACTICAL VALUE OF THE ELECTROCARDIOGRAM 

Before tlie electrograph and other less efficient instruments 
for recording the heart’s action were invented, heart disorders 
were diagnosed by the senses of hearing, touch, and sight. The 
finding of a murmur was considered a grave event because there 
was little else from which to judge what the heart was doing. 
The physician who studies his cases with the electrocardiogram 
has come to know better, for he has so much more knowledge 
on which to base his opinion. 

A murmur may be appraised when the following findings are 
given; a definite heart rate, information as to how the auricles 
and ventricles are functioning, the state of the conduction 
system, and whether one side of the heart is relatively larger 
than the other. Murmurs may help to make a diagnosis or 
prove mere harmless incidents. Or again, consider a patient 
with a slow pulse and no other symptom. One individual may 
have a slow pulse with absolutely nothing the matter with his 
heart and he may live a long and healthy life, whereas in 
another person this slow pulse may be a danger signal to in¬ 
form the physician that behind the slow pulse lies a heart block 
of the most serious kind. Without an accurate instrument of 
diagnosis, who can tell the difference? 

It is a common bad habit among doctors to trust too much to 
their memories, or perhaps to scribbled notes. A man with 
heart trouble, comes into the office. A note as to the size of the 
heart, its rate and the character of the heart sound, is perhaps 
made. The patient returns and another note is made as to 
these findings, and thus a record of the case is kept. Each one 
of these descriptions, however, must produce in the physician’s 
mind a picture of what the heart is doing. The actual photo¬ 
graph depicted by the electrocardiogram is much more valuable. 
It is like reading a prospectus of a place which we have never 
seen and visualizing the place as compared to going there and 
actually seeing it. There is nothing more valuable in following 


76 


KEY TO THE ELECTROCARDIOGRAM 


a heart patient than to have a series of these prints and thus 
compare them and actually see at a glance what progress or 
lack of progress the heart has made. 

One of the most important things about the electrocardiogram 
is the fact that it is a means of controlling the administration 
of digitalis. It is well known that in many heart disorders this 
drug is invaluable. Moreover, it has been found that large 
doses, properly given, are far more effective than small doses, 
which are frequently almost useless. Digitalis may be danger¬ 
ous as well as useful, however. As the patient becomes satur¬ 
ated, he develops extrasystoles, then heart block, which finally 
becomes so severe that the heart stops beating entirely. Before 
all this takes place, the T wave in the second and third lead of 
the electrocardiogram becomes inverted, and to those who have 
the good fortune of obtaining such tracings, it is an indication 
to watch the drug carefully. One is always in danger of giving 
too much digitalis without these tracings. 

The electrocardiogram is also at times most valuable in the 
prognosis of heart trouble. For example there is nothing in 
sinus arrhythymia to worry about, whereas heart block is 
a grave disorder. Extrasystoles may be compatible with a 
long life time of good health, but auricular fibrillation, with 
which they are so often confused, indicates a profound distur¬ 
bance. This is often the case with many cardiac disorders, the 
prognosis of which is dependent on accurate diagnosis, which 
in turn rests on accurate methods. 

There is nothing mystical or hopelessly complicated about 
electrocardiography. It is easy to learn and interpret and 
requires common sense far more than technical knowledge. 
The understanding of electrocardiograms is the criterion of 
modern, sensible, accurate handling of a patient, as compared 
to the slipshod, casual, though doubtless well-meaning ways of 
the past. 


APPENDIX 


THE PRACTICAL EMPLOYMENT OF THE 
ELECTROCARDIOGRAPH. 


CHAPTER I. 

THE SETTING UP OF AN ELECTROCARDIOGRAPHIC 

MACHINE. 

1. Place the table in position. 

2. Place the galvanometer on the table. 

3. Place the resistance box on the right end of the table, or 
on a separate table. 

4. Tuning Fork. This is placed on a separate stand at least 
four or five feet from the galvanometer. (If it is nearer than 
this, the galvanometer will pick up the make and break of the 
tuning fork.) 

5. Place the lamp stand on the table. 

6. Time Wheel. This is placed in position on a holder that 
does not touch the table. 

7. Batteries. The 8-cell storage battery is best placed in 
another room, but if inconvenient to do this, it can be placed 
under the table, beneath the galvanometer; place the 4-cell 
battery about midway underneath the table. 

8. Camera. This is placed about 1.5 meters from the 
galvanometer lens tube. 

9. Connecting the Wires. Connect the magnet circuit wires 
to the binding posts on the front legs of the galvanometer. 

10. Connect the left hand wire of the magnet circuit through 
the resistance light, and switch to the positive side of the 
battery. 

Connect the right hand wire to the ammeter and from the 
ammeter through the resistance light, and switch to the negative 
side of the battery. 


77 



78 


KEY 


TO THE 


ELECTROCARDIOGRAM 



Fig. 38.—The Hindle electrocardiograph 




















THE SETTING UP OF AN ELECTROCARDIOGRAPHIC MACHINE 


79 


11. Connect the positive post of the dry cell (which is the 
carbon) to the post marked + on the resistance box. 

Connect the negative post of the dry cell (which is the zinc) 
to the post marked — on the resistance box. 

12. Connect the lower post of the galvanometer housing 
(with insulated lead-covered wire) to the right hand post on 
the resistance box, marked “galvanometer;” and the upper 
post of the housing to the left hand post on the resistance box, 
marked “galvanometer.” The lead covering of both these wires 


Fork 



Fig. 39.—Diagram of wiring of tuning fork and time wheel. 


should be carefully grounded, and great care should be taken 
that the lead covering of the wires does not touch the posts of 
the housing or the posts of the resistance box. do prevent this 
happening, pass the wire through a glass bead, so that the bead 
is between the post and the lead insulation, t he lead coveiing 
of all these wires must be carefully grounded. 

13. Tuning Fork and Time Wheel The diagram shows how 
the tuning fork and time wheel are connected. 

14. Arc Light. The arc light should be placed in the lamp 


















80 


KEY TO THE ELECTROCARDIOGRAM 


house. The connections from the main should be made by an 
electrician. To a 15 ampere, 110 volt, direct current with cir¬ 
cuit, fuse the switch, using the polarizing connector furnished. 
The housing of the arc light should be carefully grounded, on 
account of the make and break of the arc light, or else, when 
the arc light breaks the current will affect the galvanometer. 

15. Camera Motor. Connect the camera motor to any con- 
venient lamp socket. See that the drive belt is running true and 
not slipping, otherwise your timing will not be correct. After 
putting the film in the box before putting into the camera, be 
sure it runs free. This can be ascertained by spinning the 
button which screws in the end of the shaft outside of the box. 
Be sure to turn it the right way or you will unwind the film. 

16. The Three Leads. The patient’s Lead wires are to be 
connected directly with the resistance box to the three binding 
posts marked L. A., L. L., and R. A., respectively. The wires 
used must be insulated and lead-covered. Do not use too small 
a wire. The patient’s Leads should be strung direct from the 
resistance box to the patient, keeping them as far as possible 
from the timing wheel, the vibrator, and the arc light, in order 
to avoid picking up the make and break of the frequency current. 
All unnecessary breaks in the connection, such as plugs, etc., 
are to be avoided. The wire should be continuous. 

Where the wires join the contacts connected with the patient, 
no flux or acids must be used in soldering. These connections 
must be carefully inspected to be sure they have not come loose. 
If they do the cardiogram will be very poor. 

Always use an insulation, such as a glass bead, between the 
lead covering and the contacts. This is particularly essential at 
the posts of the resistance box. The connection with the re¬ 
sistance box should be taken off occasionally and carefully 
cleaned by scraping. Do not use sand or emery, as the particles 
are apt to stick to the metal and prevent a perfect contact. The 
electrodes must also be kept clean and polished. Do not use 
an acid or alkali polish. A dry powder, such as “bon ami,” is 
preferable. 

The simplest way to clean the contacts in the resistance box 
is to take a good piece of dull finish writing paper and place it 
between the brush and the contact. Move the brush backward 
and forward, and then, holding the brush in place, pull the paper 


THE SETTING UP OF AN ELECTROCARDIOGRAPHIC MACHINE 81 


between the brush and the contact a few times, which will leave 
a clean polished surface. 

17. Ground Wire. A size 8 or 10 copper wire should be 
connected and soldered to a clean place on a running water pipe, 
and used as a ground wire. Failure to do this will, without 
exception, cause the strings in the galvanometer to break. If 
the apparatus is to be used where alternating current only is 
available, special precautions are to be taken against induction, 
in order to avoid accidents. 

The solution of this problem is to have a copper plate covered 
with carbon buried in the ground, and have the wire soldered 
to it, deeply enough so that it is well grounded. In this way 
a perfect ground will be obtained. 

The Galvanometer. The galvanometer is symmetrical in its 
construction and either microscope may be used for projection, 
as may suit conditions in the laboratory. The insturment is 
very rigid and unless located where there is an unusual amount 
of vibration, it can be used standing on a substantial wooden 
table. Have the table adjusted, so as to stand level and solidly 
on all legs in the exact position which it is intended to occupy. 
If possible, have the table legs secured by angle irons to prevent 
shifting. 

To put in the string, remove the wedge from between the 
pole shoes by taking off the top of the two bronze bars in 
front. The ivedge is held up by the bar and must be supported 
with one hand when this bar is removed, otherwise it will fall. 
The string house at the top and bottom of the pole shoes may 
be opened by turning the revolving gates with the fingers. 

Insertion of the Lenses. Unscrew the forward and rear 
microscopes until they can be removed. Underneath these will 
be seen springs whose action, with that of the nuts, moves the 
microscopes. Ball-bearing thrust collars will be seen which may 
come off with the nuts or remain on the tube. The nuts should 
be removed and laid on a clean piece of paper. The front 
microscope tube (the one towards the lamp) may now be re¬ 
moved and the 4 mm. achromatic objective screwed into it. The 
tube can now be replaced and the spring, thrust-collar, and nut 
put into place. The range of the adjustment screw is sufficient 
so that it acts as both a coarse and a fine adjustment. Screw 
the tube in until the face of the objective is about even with 


82 


KEY TO THE ELECTROCARDIOGRAM 


the corresponding pole face. The string may now be put in 
before the other microscope is in place. The other microscope 
is the projector and will carry the objective and the projection 
ocular. The microscopes fit closely in their sleeves and care 
should be taken to prevent dust and grit from getting on them 
while they are out. Lav them only on clean glass or paper. 
Once in place they will not have to be removed. 

Inserting the String. Before puting in a string, it may be • 
well to practise the manipulation, using a fine copper wire 
soldered to pins similar to those on which the strings are 
mounted. The strings are furnished soldered to brass tips and 
clamped upon a special mounting board. They are preserved 
in glass tubes. It is well to repeat the operation of taking the 
practice wire off the carrier and inserting it in the instrument 
a few times in order to become familiar with the handling of the 
manipulator, etc. 

Strings are handled with a manipulator which can be clamped 
upon the tips before they are released from the clamps on the 
board. Clamp the manipulator firmly upon the pins just beyond 
the flat plates to which the string is soldered and so that the 
soldered faces are toward the handle of the manipulator. This 
will bring the soldered faces toward the operator when the 
string is in the galvanometer. Unclamp the string from the 
board and adjust the tension screw of the manipulator, so as 
to take up the slack of the string. This is done to prevent its 
coming in contact with the pole faces in insertion. 

Tension of the String. If the string can be seen to quiver 
when lightly blown upon or when the hand is moved near it, it 
is about tight enough. 

Putting the String in Ptaee. Unless the practice wire has 
been used, it is well before transferring the string to the gal¬ 
vanometer to make sure that the string clamps in the instrument 
are approximately central and not too far back, so that the 
string will not come in contact with the pole faces. 

It is well to adjust the string clamps as far forward as 
possible, proceeding as follows: In each of the string houses 
will be found four milled screws. Loosen the four side screws 
slightly. Screw the front ones out, and follow up by turning 
the rear ones in. Do this until the brackets are as far forward 
as possible. Do not allow the adjusting serews to he taken out 


THE SETTING UP OF AN ELECTROCARDIOGRAPHIC MACHINE 83 


or to become too far removed from contact with the slides, as 
they are often difficult to put in again. With the suspension 
brackets in this position, it is quite easy to insert the string. 
Slip the string into place, and if the pin should stick in going in, 
move it up and down slightly. When back in the slot, tighten 
the string pin clamp screw—the lower one first. Use the small 
screw driver supplied for this purpose, inserting same in the 
lateral openings in the string houses. Keep a firm hold on the 
manipulator until you are sure that both pins are quite secure. 
Now remove the manipulator by unscrewing the thumb screws 
on the arms of the manipulator. 

Centering the String. The string must now be centered. 
Unless the string is accurately centered between the pole faces, 
it will not be possible to tighten and loosen it without having 
it go out of focus. If the lack of centering is considerable, it 
may not be possible to deflect the string without change of focus. 
When it is properly centered, it may be deflected to the extreme 
edge of the field or tightened and loosened over the entire work¬ 
ing range without material change of focus at zero. 

Working Light for the String. On account of the extreme 
fineness of the string, it must be illuminated in order to be seen 
by the unaided eye. Use an incandescent lamp, with a small half 
shade brightly polished inside and set upon an adjustable stand 
before the instrument, as a source of light in manipulating the 
string. By moving this light up and down and sidewise, dif¬ 
ferent parts of the string can be so illuminated as to be plainly 
visible, even fibers as small as one micron. Do not try to see 

7 v 

the entire length of the fiber at once, but illuminate first one 
end and then the other. Illuminate the upper end and looking 
in from in front, adjust the lateral centering micrometer until 
the string is seen to bisect the space between the pole faces. 
Do the same at the lower end. To adjust in the anteroposterior 
direction, look in through the lateral opening at the top, through 
which the screw driver was inserted in clamping the string, 
and adjust until the string is opposite the pole face. At the 
bottom, it is not possible to look in directly, because the magnet 
is in the way, but a small mirror such as that of a laryngoscope, 
held at a suitable angle, and looked at from in front, will enable 
one to see the string from the lateral aspect, provided the lamp is 
in proper position. It is to be adjusted in the same way as the 



84 


KEY TO THE ELECTROCARDIOGRAM 


upper end. After the string has been centered with the pole 
faces, adjust the lamp, so as to illuminate the middle portion 
of the string. Looking through the hole in which the rear 
microscope belongs, the illuminated string can be seen against 
the condenser lens as a background. The microscopes have been 
adjusted at the factory and the string will appear to bisect the 
lens. In the event of their having been moved in transportation, 
adjust by means of the centering screws until the string appears, 
as mentioned before, to bisect the microscopes. 

The other objective is now put in its tube and inserted in 
the galvanometer. In inserting the tube and lens with the 
string in place, take care that the spring does not catch and 
cause the objective to rebound against the string. Screw up 
both fine adjustment nuts until the objectives are near the 
string. The microscopes operate about 1 mm. from the string. 
Stops are provided to prevent touching. Adjust the illuminat¬ 
ing apparatus, so as to throw light through the front microscope 
(condenser) and, using the centering screws, adjust the other 
microscope until light comes through. This can be most easily 
seen by holding a white card about a foot from the projection 
microscope. Cautiously focus the rear microscope in and out, 
and if the front microscope is properly adjusted to be central 
with the string as described above, the shadow of the string 
will presently appear. The projection ocular may now be put in. 


CHAPTER II. 


RUNNING THE MACHINE. 

Focusing the Lenses . In focusing tlie lenses it is an es¬ 
sential thing to have a perfect alignment. To obtain this we 
have to remove the front lens of the microscope, and get the 
shadow of the string exactly in the center. The shadows of the 
circles seen must also be perfectly centered. The front lens of 
the microscope can then be replaced and screwed in until the 
shadow of the string is obtained. 

If no shadow of the string is seen now, it is because the 
alignment is still at fault. The prismatic colors around the 
circle of light will tell this defect, and by moving the microscope 
in different directions until the circles are perfectly even, and 
the coloring the same all the way round, it is possible to get a 
correct centering. 

After the shadow of the string is obtained, one should observe 
the coloring of the prismatic shades. The best results for a 
photograph are obtained when the inside circle of the colors is 
a purple one. The diaphragm is then cut down till the light 
just covers the slot in the camera. You now move the shadow 
of the string until it is passed all the way across the lens of the 
camera, then reverse the current and pass it back in the other 
direction. The shadow should be of the same density in all 
positions. If this detail is not correct, one gets a very poor 
film. If the string does not appear of the same density in all 
positions, it is because it is not perfectly perpendicular in the 
housing, and the front and back of the microscope are not in 
perfect alignment. 

A denser shadow of the string is obtained, and also much 
greater leeway in focusing, if you set the tension of the string 
so that it moves exactly 1 mm. when 1 millivolt of current is 
added. Then remove the projector and move the camera away 
from the microscopes until I millivolt moves exactly 1 milli¬ 
meter. If this is carefully attended to, there is much greater 
leeway and this adjustment can be run for months without any 


85 


86 


KEY TO THE ELECTROCARDIOGRAM 


trouble with the focusing. A very much more exact reading 
of the excursions of the string is possible. 

The Timer. In connection with the timer a tuning fork is 
used. This is done because the vibrations of the fork give an 
exact make and break which gives a rhythm for the time wheel. 
The vibrations regulate the lines to one twenty-fifth of a 
second. The tuning fork should be set up on a separate table, 
otherwise the string will be disturbed by the tuning fork vibra¬ 
tions. The fork is so adjusted that it starts automatically when 
the switch is turned in. There is very little trouble in keeping 
the timer in operation. If the spokes of the timing wheel are 
shortened so that the shadow passes only part of the way 
across the film, the short shadows of the spokes do not interfere 
with the reading of the electrocardiogram. 



Fig. 40.—Irregular curve indicating broken Lead wires: the broken ends, 

however, being in contact. 


Arc Light. If the arc light is used, the metal box inclosing it 
should be carefully grounded, otherwise when the arc light 
breaks, the current will affect the galvanometer. 

Failure to get Current from the Patient. Another accident, 
which is fairly frequent, is a failure to obtain the current from 
the patient and record it in the galvanometer. 

The reason for this is that the Lead wires have become wholly 
or partially broken where they bend near the contacts. This 
gives rise to a very misleading state of affairs, because where 
the wires are not entirely broken, the current may pass and it 
may not. This depends on the position of the wires. If the 
broken ends happen to be touching, a partial current comes 
through. This occurrence causes a special action of the galvano- 

















































































RUNNING THE MACHINE 


87 


meter. The current appears very sluggish and has the appear¬ 
ance of over shooting. (See Fig. 40.) 

As will be seen by the illustration, the shadow of the string 
goes up too far, and travels too slowly. 

This same appearance will manifest itself if you have neg¬ 
lected to turn the patient’s currents completely in on the pro¬ 
tective resistance. This means that the patient’s currents are 
not getting through. 

Corrosion of the Lead Wires. The Lead wires, where con¬ 
nected with the control box, are apt to become corroded. They 
should he taken off at least every two months, and scraped. 
This will avoid a peculiar appearance in the galvanometer chart. 

Testing the Machine. In testing out the machine, to see if 
it is running in perfect order, before one puts the patient in 



Fig. 41.—Testing the machine; effect of winding of a wire carrying an inter¬ 
rupted current around a lead wire. The curve from the straight wire is shown 
on the left, that from the wound wire is on the right. 


connection with it, the two arm contacts are placed one on the 
top of the other, and kept tightly together by using a wooden 
clothes-pin. Then Lead I is turned in. When this is done 
there should not be any movement apparent upon shadow of the 
string. Next 1 millivolt of current is added and the tension of the 
string is adjusted until 1 millivolt moves 1 centimeter. Without 
changing the tension of the string, test Lead II and Lead III in 
the same way. They should read the same. 

Other factors which may cause differences between the Leads 
are: dirty contacts; corroding contacts; neglect to wash the 
bandages perfectly after being used. 


» > > 































































































CHAPTER III 


CORRECT OPERATION OF THE MACHINE WITH THE 

PATIENT CONNECTED. 

Before detailing the steps of the procedure of operating the 
machine, a word may be said here as to the arrangement of the 
person for whom the electrocardiogram is desired. The patient 
must be quiet, relaxed, undisturbed, since muscular tension or 
movements, conversation, coughing, shivering, or restlessness, 
interfere with the work by causing irregular motions of the 
string. All such motions, and any disturbance caused by ir¬ 
regularities of the camera or the film, can, however, be disre¬ 
garded, as they differ greatly from the regular curves of the 
tracing. 

The wet cloths which are put on the patient in making the con¬ 
nection should always be put on quite hot; when this is done the 
warmth of the body will tend to keep them at body temperature. 
If they are put on cold, the effect of the cold on the skin causes 
a resistance, and will have the effect of pulling the string of the 
galvanometer over to one side. This is avoided, as said, by 
heating the cloths. 

The Use of Fresh Water for Soaking the Bandages. The 
usual practice is to apply bandages soaked in salt solution 
around the patient’s limbs; but the writer has found that a very 
much more detailed reading is obtained when fresh water is 
used. The reason for this is that the action of the salt on the 
metal gives rise to currents which pass through the galvano¬ 
meter. These currents have to be compensated for and make 
the reaction of the galvanometer much less sensitive to the 
minute currents originated in the heart. The writer has col¬ 
lected a great deal of material which proves the greater delicacy 
of reactions obtained with the use of fresh water. The ac¬ 
companying illustration (Fig. 42) shows the very much finer 

differentiation obtained by the use of fresh water. 

•/ 

Effect of the Nauheim Bath on the Galvanometer Reactions. 
With the use of distilled water on the bandages, it is possible 
to pick up any muscular action of the body, even of an extremely 



< 



C C 


CORRECT OPERATION OF MACHINE WITH PATIENT CONNECTED 89 


slight force, provided that the skin where the contacts are made 
is perfectly clean. This precaution eliminates the so-called skin 
currents, which are probably nothing more or less than the 
action of secretions of the skin. 

Very interesting observations have been taken in live dif¬ 
ferent persons, all of whom were old patients and had had 
records taken a number of times. Records were taken within an 
hour after they had had Nauheim baths. In all live of these 
cases no skin resistance was found; in other words, the records 
could have been taken absolutely without the resistance box. 
Although, of course, the series of live is a small one, the fact is 
a striking one, and suggests that there is a field for very in¬ 
teresting observations along this line. 



I : ; : : : : ' i 

Fig. 42.—Illustrating the finer differentiation obtained by the use of fresh water 
in making contacts. 1, Fresh water; 2, salt solution. 

Taking the Electrocardiogram. The various steps necessary 
for taking an electrocardiogram are as follows: 

Step 1. The patient is placed in the chair, ready for 
examination. 

Step 2. Compensating Current. This is one that is made use 
of in order to compensate the current received from the patient, 
and also other currents. For instance, if the patient’s current 
is positive or negative, then current is introduced which is suf¬ 
ficient to bring the balance back to the center. 

Step 3. Indicator of Leads . The Leads are marked off on an 
indicator. This is turned off to zero before commencing. 

Step. 4. The Magnet. The magnet is excited. The ammeter 














90 


KEY TO THE ELECTROCARDIOGRAM 


should read at least 2% amperes. The operator should wait 
until the indicator comes to rest, as when the magnet is first 
excited there are vibrations of the pointer. 

Step 5. The String Galvanometer. This is now fully con¬ 
nected. A dial indicates when the full connection is made. 

Step 6. Tension of the Galvanometer. To reach a safe 
tension, 1 millivolt of the 1 millivolt dial is added. 

Step 7. Testing Tension. To do this the string is loosened 
or tightened, until the shadow moves 1 centimeter in response 
to 1 millivolt of current. This is the usual standard. 

Step 8. The added millivolt step, used for testing is now 
removed and the indicator moves back to zero. 

Step 9. Disconnect the galvanometer by turning the dial 
to zero. 



Fig. 43.—Illustrating a continuous vibration of the string which usually indicates 

dust on the contacts of the resistance box. 

Step 10. Connecting the Patient. This is done through the 
compensation box (box holding the coils for the compensating 
current). 

Connection of the patient for Lead 1 is made by currents from 
the right arm and left arm (current across the base of the 
heart). 

Step 11. Reconnect galvanometer, one step. The current 
from the patient is put in very gently, through the protecting 
resistance coils; if this caution is not observed the suddenness 
of the current would throw the string against the magnet and 
break it. The resistance is reduced one step at a time, until 
there is nothing left but the patient’s currents and compensat¬ 
ing current. 

Step 12. The current from the patient is compensated until 
the shadow of the string is exactly in the center. 

Step 13. Gradually add more of the patient’s current to the 
galvanometer. 
























CORRECT OPERATION OF MACHINE WITH PATIENT CONNECTED 91 


Step 14. Again compensate the current from the patient 
until the shadow is in the center. 

Step 15. There is nothing left now hut the patient’s currents 
and compensating current. 

Step 16. Compensate until the shadow is in the center. 

Step 17. Tension of String. The patient, being now fully 
connected, loosen or tighten the string until it moves 1 cm. to 1 
millivolt of current. 

Sep 18. Start film, by turning handle. 

Step 19. Lead I is now taken (right arm and left arm). 

Step 20. All connections are now turned off, on both the 
patient and the galvanometer. 

Step 21. Prepare for Lead II. To do this, before turning in 
string galvanometer for Lead II, the tension should be tightened 
by a half turn of the wheel of the micromic screw that governs 
the galvanometer tension in the housing (metal casing of the 
galvanometer), 

Step 22. Repeat Steps 5, 6, 7, 8, and 9. 

Step 23. Connect the patient for Lead II (right arm and left 
leg). Repeat steps 11, 12, 13, 14, 15, 16, 17 and 18. Take Lead 
II, then repeat step 20. 

Step 24. Prepare for Lead III taking the same steps as for 
Lead II. Finally turn all indicators fully off. 

Note : Safe Tension of the Machine. On account of the 
vibrations of the earth, expansion and contraction due to at¬ 
mospheric variations, extraneous movements and shaking, the 
tension of the string should be left in such a condition that it 
moves % cm. when 1 millivolt is added. The machine can 
be safely left in this tension for weeks or months. 

Magnet Switch. The batteries should be disconnected by 
opening the magnet switch, as soon as possible after finishing 
with the patient, otherwise they run down very quickly. 

Difficulties and Their Reasons. 

Slight Continuous Vibration of the String. When one starts 
to turn in the patient’s currents, and a slight continuous vibra¬ 
tion of the galvanometer string appears (Fig. 43), it is almost 
sure to be due to dust on the contacts of the resistance box. 
To remedy this, disconnect the patient, and turn the compensat- 


92 


KEY TO THE ELECTROCARDIOGRAM 


ing resistance backwards and forwards a dozen times or so, 
which pushes the dust off temporarily and removes the obstruc¬ 
tion. This is only of temporary benefit, however, and when 
through with the patient, it is necessary to clean the box thor- 
ougly. The slightest sign of this vibration warns the operator 
that it is necessary to clean the box as described in Chapter I, 
paragraph 16. 

Continuous Vibrations in all Leads. If continuous vibrations 
appear in all Leads the cause may be sought in a crystallization 
of the wires that run from the galvanometer housing to the 
control box. These should be taken out and replaced with new 
ones. This is not a very frequent accident, however. The 
crystallization is probably caused by the fact that these wires 
run underneath a very powerful magnet, which acts thus on 
the copper. 

Vibration of the Floor. When one steps up to the camera 
a slight vibration of the floor is started, which is picked up by 
the galvanometer string. The operator should always wait for 
this vibration to subside before turning on the camera. If he 
does not take this precaution the first part of the Lead presents 
an appearance of fibrillation. 

An appearance of fibrillation is also caused by any person 
walking across the floor while the film is being taken. One 
should then stop the film and wait until the vibration has sub¬ 
sided before starting to take the Lead again. 

Any muscular movement of the patient, such as talking or 
coughing will pull the string out of center. 

Precautions To Be Observed. 

After finishing with the patient, lie very sure that all the 
connections are turned off to zero. 

Before making new connections with the patient and the gal¬ 
vanometer, lie sure that everything has been previously turned 
off to zero. 

Unless these precautions are strictly adhered to there will 
always be trouble. The most frequent mishap is that one finds 
the string has disappeared, and on searching for it, it is found 
touching the magnet (shoe of the magnet) and stuck fast to it. 


CORRECT OPERATION OF MACHINE WITH PATIENT CONNECTED 93 


If this lias happened, a frequent mistake is to try to free it 
by tightening it, with the result that the increased tension causes 
the string to break. 

Method of Freeing the String. Take out the wedge and with 
a very fine hair (a coarse one will not serve) pry the string 
loose. To do this it is necessary to use a magnifying glass, 
as the string is barely perceptible to the naked eye. 

i 

General Considerations. 

Sensitiveness of the String Galvanometer. The galvanometer 
is extremely sensitive to currents that are passed through it, 
and therefore very liable to pick up outside currents such as 
those from radiographic wires, or those of an rr-ray machine 
working anywhere in the neighborhood. 

This sensitivity to vibrations is illustrated by the fact that 
the writer has even been able, by having a contact with the lead 
covering of the Lead wires on the post of the compensating box, 
to pick up the vibrations when an ordinary front door bell rang 
two floors below and set the string in vibration. Such vibrations 
are of a very regular character. 

Vibrations that are not regular in time or force are due to 
vibrations of the earth, and these can be eliminated by keeping 
the contacts clean and avoiding loose connections. 

Character of the Electrocardiographic Records. It may be 
asked what the electrocardiogram really represents. What the 
machine does, in effect, is to record the utilization of energy 
by the body, in any of its processes, the heart ’s activity being 
the best known and most thoroughly studied of these. This is 
shown in a striking way during the taking of a record of a person 
who has dropped to sleep in the chair while having the Leads 
taken. At the precise moment of time at which the individual 
drops asleep, there is a distinct point at which the energy is 
cut down, and this diminution makes itself evident in the record 
by the lessening of the height and force of the waves. With the 
shutting down of cerebral activity there is a coincident reduc¬ 
tion in the heart’s energy output. 

While the recording of the heart ’s energy is a comparatively 
complete branch of study, other uses of the electrocardiograph 
are merely in the experimental stage, although they offer a 


94 


KEY TO ELECTROCARDIOGRAM 


wonderful opening* for research and experimentation. The 
string* galvanometer has been applied to recording* of the action 
of the brain, which is a more direct process than that applied 
to the heart. It can also be used in connection with intestinal 
muscular activity. In experiments directed toward making 
records of other types of energy that may be detected by this 
machine, better results may be gained by using* very much 
smaller contacts than those used in electrocardiographic work. 
The latter have a surface measurement of about 9 square inches. 
Contacts applied to the temples are quite small; those applied to 
the abdomen in tracing movements of the colon may be larger, 
but it is a matter of exact experimentation to determine which 
size of contact procures the best result. With suitable contacts 
it is possible to make records of the brain or of the gastrointes¬ 
tinal tract which may lead to the adoption of this machine in 
a widely extended field of medicine. 


INDEX 


Adams-Stokes disease, heart block in, 39 
Angina pectoris, downward T wave in, 
17 

Aortic valvular disease, downward T 
wave in, 17 
Arrhythmia, sinus, 27 
Auricles, activity of, shown by the P 
wave, 12, 14 

premature contraction of the, 40 
rapid action of the, 52 
trembling paralysis of the, 55 
Auricular contraction, wave (P) indi¬ 
cating, 12 
fibrillation, 55 
flutter, 52 

Autograph, electric, of the disordered 
heart, 19 

of the healthy heart, 12 

Bundle of His, 32 
lesion of, 64. 

Cardiology, use of graphic methods in, 3 
Children, sinus arrhythmia in, 27 
Conduction system, irregularities due to 
defect in the, 32 
Contraction, premature, 40 
Coupling of ventricular extrasystoles, 45 

Dextrocardia, inversion of waves in Lead 
I caused by, 7, 63 

Diagnosis, value of the electrocardio¬ 
gram in, 75 

Digitalis, control of the administration 
of, by the electrocardiogram, 76 

Electrocardiogram, caution against too 
great reliance upon, in diagno¬ 
sis, 10 

clinical value of the, 22 
of a healthy person, 12 
practical value of the, 75 
scheme of the normal, 13 
taken at a distance, 9 
taking the, 89 
time element in the, 24 
what it really represents, 93 
Electrocardiograph, correct operation of 
the, with the patient connected, 88 
history of the, 5 
practical employment of the, 77 
principle of the, 6 
running the, 85 
arc light, 86 

compensating current, 89 
connecting the patient for the sev¬ 
eral Leads, 90 

corrosion of the Lead wires, 87 
difficulties, 91 


failure to get current from the pa¬ 
tient, 86 

focusing the lenses, 85 
fresh water for bandages, 88 
indicator of Leads, 89 
magnet, 89 
magnet switch, 91 

Nauheim bath, effect of, on the 
galvanometer reaction, 88 
precautions to be observed, 92 
safe tension of the machine, 91 
tension of the galvanometer, 90 
testing the machine, 87 
testing the tension, 90 
timer, 86. 
vibrations, 91. 
sensitiveness of the, 93. 
setting up of the, 77 
arc light, 79. 
camera motor, 80. 
connecting the Lead wires, 80 
connecting the wires, 77 
cleaning the contacts, 80 
galvanometer, 81 
ground wire, 81 
illumination of the string, 83 
insertion of the lenses, 81 
insertion of the string, 82 
Lead wires, 80 
string, 82 
time wheel, 77, 79 
tuning fork, 77, 79 
testing the, 87 

uses of, other than for study of the 
heart, 93 
Extrasystoles, 40 
auricular, 42 

relation of, to tachycardia, 50 
ventricular, 43 

compensatory pauses in, 44 

Fibrillation, auricular, 55 

Flutter, auricular, 52 

F-waves in auricular fibrillation, 56 

Galvanometer, string, history of the, 5 
Graphic methods, use of, 1 

Heart, electric autograph of the dis¬ 
ordered, 19 
of the healthy, 12 

electric currents in the, giving rise 
to the three Leads, 8 
premature contraction of the, 40 
rate of the, shown by the electrocar¬ 
diogram, 17 

relative activity between the right and 
left sides of the, shown in the 
electrocardiogram, 71 


95 



96 


INDEX 


Heart-block, 32 
complete, 37 
partial, 33 
His, bundle of, 32 
lesion of, 64 

Hypertrophy, unilateral, of the heart, 
shown in the electrocardiogram, 

71 

Industries, use of graphic methods in, 2 

Lead I, downward T-wave in, 17 
connecting the patient for, 90 
current in, 7 

inversion of waves in, caused by dex¬ 
trocardia, 7, 23, 63 

Lead II, connecting the patient for, 91 
current in, 7 
downward T-wave in, 17 
Lead III, connecting the patient for, 91 
current in, 7 
downward T-wave in, 17 
Leads, changes in the, showing unilateral 
hypertrophy, 71 
definition of, 6 
reading of the, 18 
significance of the three, 7 

Lead-wires, connecting the, 80 

Medicine, graphic charts in, 3 
Myocardium, dysfunction of the, 41 

Nauheim bath, effect of, on the galvan¬ 
ometer reaction, 88 

Pace-maker, 32 

Pain in lesion of the bundle of His, 64 
Pause, compensatory, in ventricular ex¬ 
trasystoles, 44 

P-R interval, lengthening of the, in 
heart-block, 33, 36 

Prognosis, value of the electrocardio¬ 
gram in, 76 

P-R-T complex destroyed in complete 
heart-block, 37 
Pulse, alternating, 59 
cause of, 60 
rapid, 47 

sympathetic control in relation to the, 
30 

vagus control in relation to the, 30 
Pulsus alternans, 59 

bigeminus in ventricular extrasystoles, 
45 

P-w’aves, absence of, in auricular fibril¬ 
lation, 56 

distorted, in premature auricular con¬ 
traction, 41 

in auricular extrasystoles, 41 
in auricular flutter, 52 
in complete heart-block, 38 
in mitral stenosis, 62 
in partial heart-block, 34 
in paroxysmal tachycardia, 48 


in premature auricular contraction, 23 
in tachycardia, 48 
significance of the, 12, 14 

Q-R-S group in right bundle branch 
lesions, 66 

Q-wave, significance of the, 14 

Right bundle branch, lesion in the, 64 

R-T-waves, distorted, in premature ven¬ 
tricular contraction, 43 
in auricular fibrillation, 57 
in complete heart-block, 38 
in tachycardia, 48 
in ventricular extrasystoles, 43 

R-wave in aortic disease, 63 
in congenital cardiac defects, 63 
in disproportion between the two sides 
of the heart, 71 

in left ventricular predominance, 18 
in left ventricular premature beat, 23 
in mitral stenosis, 62 
in pulmonary stenosis, 63 
in right bundle branch lesions, 18 
in right ventricular premature beat, 23 
in unilateral preponderance of the 
heart, 71 

significance of the, 12, 15 

Sinus arrhythmia, 27 

Stokes-Adams disease, heart-block in, 
39 

S-wave, significance of the, 15 

Tachycardia, auricular, 52 
simple paroxysmal, 47 

means of arresting, 51 

Time element in the electrocardiogram, 

24 

Transmission, delayed, significance of, 

25 

Tripling of ventricular extrasystoles, 45 

T-wave, downward, significance of the, 
15 

in angina pectoris, 17 
in aortic disease, 63 
in right bundle branch lesions, 66 
significance of the, 12, 15 

U-wave, significance of the, 15 

Vagus control, loss of, in paroxysmal 
tachycardia, 47 

Valvular disease, electrocardiographic 
evidences of, 62 

Ventricle, activity of, shown by the R- 
and T-waves, 12, 15 
premature contraction of the, 43 

Ventricular contraction, waves (R and 
T) indicating, 12 

Vibrations causing difficulty in running 
the machine, 91 

Waves, normal limits of the, 19 

relation of, to the heart action, 12, 16 
schema of the, 14 


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